Edmund Sixtus Muskie was born on Sunday, March 28, 1914 in Rumford, Maine. He was born after their first child, Irene (b. 1912), and before his brother Eugene (b. 1918) and three sisters, Lucy (b. 1916), Elizabeth (b. 1923), and Frances (b. 1921). His father, Stephen Marciszewski, born in raised in Jasionka, Poland and worked as an estate manager for minor Russian nobility. He immigrated to America in 1903 and changed his name to Muskie from "Marciszewski" in 1914. He worked as a master tailor and Muskie's mother, Josephine (née Czarnecka) worked as a housewife. She was born to a Polish-American family in Buffalo, New York. Muskie's parents married in 1911, and Josephine moved to Rumford soon after.

Jane Frances Grey was born February 12, 1927 in Waterville to Myrtie and Millage Guy Gray. Growing up she was voted "prettiest in school" in high school and at age 15, started her first job in a dress shop earning $3.49 a week. At age 18, she was hired to be a bookkeeper and saleswoman in an exclusive haute couture boutique in Waterville. While there a mutual friend tried to introduce her to Muskie while he was working the city as a Lawyer. She had Grey model the dresses while he was walking to work. Muskie came into the shop one day and invited her to a gala event. At the time she was 19 and he was 32; their difference in age stirred controversy in the town. However, after eighteen months of courting Grey and her family, she agreed to marry him in a private ceremony in 1948. Gray and Muskie had five children: Stephen (b. 1949), Ellen (b. 1950), Melinda (b. 1956), Martha (b. 1958), and Edmund Jr. (b. 1961). The Muskies lived in a yellow cottage at Kennebunk Beach while they lived in Maine. The Mayer of Waterville made May 20, 1957 "Jane Muskie Day" in honor of Jane and Muskie.

Muskie's first language was Polish; he spoke it as his only language until age 4. He began learning English soon after and eventually lost fluency in his mother language. In his youth he was an avid Fisherman, hunter, and Swimmer. He felt as though his given name was "odd" so he went by Ed throughout his life. Muskie was shy and anxious in his early life but maintained a sizable amount of friends. Muskie attended Stephens High School, where he played baseball, participated in the performing arts, and was elected student body President in his senior year. He would go on to graduate in 1932 at the top of his class as valedictorian. A 1931 edition of the school's newspaper noted him with the following: "when you see a head and shoulders towering over you in the halls of Stephen's, you should know that your eyes are feasting on the Future President of the United States."

Influenced by the political excitement of Franklin D. Roosevelt's election to the White House, he attended Bates College in Lewiston, Maine. While at college, Muskie was a successful member of the debating team, participated in several Sports, and was elected to student government. Although he received a small scholarship and New Deal subsidies, he had to work during the summers as a dishwasher and bellhop at a hotel in Kennebunk to Finance his time at Bates. He would record in his diaries occasional feelings of insecurity to his more wealthier Bates peers; Muskie was fearful of being kicked out of the college as a consequence of his socioeconomic status. His situation would gradually improve and he went on to graduate in 1936 as class President and a member of Phi Beta Kappa. Initially intending to major in mathematics he switched to a double major in history and government.

Upon his graduation, he was given a partial merit-based scholarship to Cornell Law School. After his second semester there, his scholarship ran out. As he was preparing to drop out, he heard of an "eccentric millionaire" named william Bingham II who had a habit of randomly and sporadically paying the university costs, mortgages, car loans, and other expenses of those who wrote to him. After Muskie wrote to him about his immigrant origins he secured $900 from the man allowing him to Finance his final years at Cornell. While in law school he was elected to Phi Alpha Delta and went on to graduate cum laude, in 1939. Upon graduating from Cornell, Muskie was admitted to the Massachusetts Bar in 1939.

He then worked as a high school substitute Teacher while he was studying for the Maine Bar examination; he passed in 1940. Muskie moved to Waterville and purchased a small law practice–re-named "Muskie & Glover"–for $2,000 in March 1940.

In June 1940, President Roosevelt created the V-12 Navy College Training Program to prepare men under the age of 28 for the eventual outbreak of World War II. Muskie formally registered for the draft in October 1940 and was formally called to deck officer training on March 26, 1942. At 28, he was assigned to work as a diesel Engineer in the Naval Reserve Midshipmen's School. On September 11, 1942 he was called to Annapolis, Maryland to attended the United States Naval Academy. He left his law practice running so "his name would continue to circulate in Waterville" while he was gone. He trained as an apprentice seaman for six weeks before being assigned the rank of midshipman.

In January 1943, he attended diesel engineering school for sixteen weeks before being assigned to First Naval District, Boston in May. Muskie worked on the USS YP-522 for a month. In June he was assigned to the USS YP-566 at Fort Schuyler in New York where he worked as an indoctrinator. In November 1943 he was prompted to Deck Officer. He trained for two weeks in Miami, Florida at the Submarine Chaser Training Center. After that he was relocated to Columbus, Ohio to study reconnaissance in February 1944. In March he was promoted to junior-level Lieutenant. Muskie was stationed at California's Mare Island in April temporarily before formally engaging in active duty warfare.

He began his active duty tour aboard the U.S.S. Brackets. His vessel was in charge of protecting U.S. convoys traveling from the Marshal and Gilbert Islands from Japanese submarines. The U.S.S. Brackets escorted ships to and from the islands for the majority of summer 1994. In January 1945, the ship engaged and eventually sunk a Japanese cargo ship headed for Taroa Island. After a few more months of escorting ships to and from the two islands, the ship was decommissioned. He was discharged from the Navy on December 18, 1945.

He was assigned to the committees on federal and military relations during his first year. Muskie advocated for bipartisanship which won him over wide-spread support across political parties. On October 17, 1946, his law practice sustained a large fire costing him an estimated $2,300 in damages. However a yearly stipend of $800 and help from other Business Leaders who were affected by the fire quickly re-started his practice.

His work with city ordinances in Waterville prompted locals to ask him to run in the 1947 election to become Mayor of Waterville against banker Russel W. Squire. Due to incumbency advantage, Muskie lost the election with 2,853 votes, 434 votes behind Squire. Some historians believe that his loss had to do with his inability to gain traction with Franco-American voters.

Muskie was against the rapid accumulation of highly developed weaponry during the 1950s and 1960s as he thought that would inevitably lead to a nuclear arms race that would erode international trust and cooperation. He spoke frequently with the government executives of Cold War allies and that of the Soviet Union urging them to suspend their programs in pursuit of global security. Muskie's inclinations were confirmed during the early 1970s when Russia split from the U.S. and accumulated more warheads and anti-ballistic missile systems. In November 1980, Muskie stated that Russia was interested in pursuing a "more stable, less confrontational' relationship with the United States." He criticized the stances undertaken by Ronald Reagan multiple times during his presidential campaign expressing disdain for the calls to reject the SALT II treaty. Muskie, throughout his political career, was deeply afraid of global nuclear war with the Soviet Union.

He later returned to the House to start his second term in 1948 as Minority Leader against heavy Republican opposition. Muskie was appointed that chairman of the platform committee during the 1949 Maine Democratic Convention. During the convention, he brought together a variety of the political elite of Maine — notably Frank M. Coffin and Victor Hunt Harding — to plan a comeback for the party. On February 8, 1951, Muskie resigned from the Maine House of Representatives to become acting Director for the Maine Office of Price Stabilization. He moved to Portland soon after and was assigned the inflation-control and price-ceiling divisions. His job required him to move across Maine to spread word about economic incentives which he used to increase his name recognition. He served as the regional Director at the Office of Price Stabilization from 1951 to 1952. Upon leaving the Office he was asked to join the Democratic National Committee as a member; he served on the committee from 1952 to 1956.

In April 1953, while working on renovations for his family home in Waterville, Muskie broke through a balcony railing falling two flights of stairs. He landed on his back, knocking unconscious. He was rushed to the hospital where he remained unconscious for two days. Doctors believed that he was in a coma so they gave him comatose-speicifc medication which caused him to regain consciousness but start to hallucinate. Muskie tried to jump out of the hospital window but was restrained by staff members. After a couple of months, through physical rehabilitation and corrective braces, he was able to walk once more.

His governorship exploited multi-factionalism in the Republican Party leading to a vast expansion of the Democratic Party in Maine. From 1954 to 1974, the party doubled in size, while the Republican Party steadily decreased from 262,367 to 227,828 registered members. Numerous state politicians mimicked his political style to push their programs through various local governments and garnered electoral success. His executive appointments of moderate politicians shifted the entire Republican establishment in the state to the left. This shift garnered comparisons to Hubert Humphrey's influence in Minnesota and George McGovern's impact in South Dakota. During his last months as governor he changed his office's term from two years to four years. Shortly before leaving office he moved Maine's general election date from September to November conclusively ending the notion that "as Maine goes, so goes the nation". This was attempted thirty-six times before Muskie brought about a constitutional amendment that moved the date.

Muskie was given honorary degrees from Portland University (1955), Suffolk University (1955), University of Maine (1956), University of Buffalo (1960), Saint Francis College (1961), Nasson College (1962), Hanover College (1967), Syracuse University (1969), Boston University (1969), John Carroll University (1969), Notre Dame University (1969), Middlebury College (1969), Providence College (1969), University of Maryland (1969), George Washington University (1969), Northeastern University (1969), College of william and Mary (1970), Ricker College (1970), St. Joseph's College (1970), University of New Hampshire (1970), St. Anselms College (1970), Washington and Jefferson College (1971), Rivier College (1971), Thomas College (1973), Husson College (1974), Unity College (1975), Marquette University (1982), Rutgers University (1986), Bates College (1986), Washington College (1987), and University of Southern Maine (1992).

On September 10, 1956, Muskie was re-elected Governor of Maine with 180,254 votes (59.14% of the vote) against Republican Willis A. Trafton. He won 14 of the 16 counties. He began his second term by aggressively enforcing environmental standards. In 1957, he sanctioned a $29 million dollar highway bond. This bond funded the largest road construction ever undertaken by Maine. The highway included 91 bridges and was extended in 1960 and 1967 by Interstate 95.

During his tenure as Governor he retained a reputation for increased spending in public education, subsidized hospitals, modernized state facilities, and cumulatively raised state sale taxes by 1%. He added $4 million to infrastructure development focusing on roads and river maintenance. Muskie pushed aggressive economic expansionism. In 1957, he founded the Maine Guarantee Authority which combated economic maturation-related job loss making making capital more accessible for Business owners. Muskie also sporadically lowered sales tax, increased the minimum wage and furthered labor protections leading to a marked increase in consumer spending. He amended the constitution of Maine in order divert $20 million in public funds into private investment. His increased subsidies to expensive institutions such as public primary and secondary schools as well as universities. Although initially founded in 1836, the Maine State Museum was closed and reopened six time before Muskie permanently endowed it in 1958.

Muskie's first contestation for the Senate of the United States was in 1958. He ran in the 1958 elections against incumbent Republican Senator Frederick G. Payne. Muskie won the election with 60% of the vote against Payne's 39%. He was one of the 12 Democrats who overtook Republican incumbents and established the party as the party-of-house during the election cycle. The New York Times reported that during this election that the absentee ballots requested for Democrats increased considerable signaling voter-discontent with Republican ideology. This election was considered the largest single-party gain in the Senate’s history.

He served his entire career in the Senate as a member of the Committee on Public Works, a committee he used to execute the majority of his environmental legislation. He served on the Committee on Banking and Currency from 1959 to 1970; the Committee on Government Operations until 1978. As a member of the Public Works Committee, he traveled to the Soviet Union in 1959. He sponsored the Intergovernmental Relations Act, later that year.

Since Muskie left office as the U.S. Secretary of State, Writers, historians, scholars, political analysts and the general public have debated his legacy. Particular emphasis is placed on his impact in the Environmentalist and civil rights movement; bureaucratic advancement, and diplomacy. Overall supporters of Muskie point to a expansion of environmental protection, preservation, and security. Numerous historians have noted him as "the father of the 1960s environmental movement in America". His accomplishments in environmentalism established two of the foremost measures in international environmental policy: the Clean Water Act of 1963 and Clean Air Act of 1972. His contributions to the Clean Air Act were so great that the bill was nicknamed the "Muskie Act". These two laws have been credited as the first major step to launching the wider environmentalism movement both in the U.S. and to some extent, the rest of the Free World. Harvard University Historian Richard Lazarus summarized Muskie's legislative legacy with the following:

He was awarded the Guardian of Berlin's Freedom Award from the U.S. Army Berlin Command in 1961. In 1969, he was inducted in the American Academy of Arts and Sciences alongside Ted Kennedy, George McGovern, Walter Mondale, Shirley Chisholm, and Bella Abzug.

In 1962, he co-founded the United States Capital Historical Society along with other members of congress. The same year, member of Congress elected him to serve as the first chair of the Subcommittee on Air and Water Pollution. In 1963, he was the first to sponsor a new Act to regulate air pollution. The Clean Air Act of 1963 was written and developed by Muskie and his aide Leon Billings.

The public perception of his civil rights advancement has endured. A champion of the civil rights movement in the United States, he publicly criticized J. Edgar Hoover's Federal Bureau of Investigation, which was at the time considered political suicide as Hoover often spied and attempted to smear his opponents. Muskie also was instrumental in the passage of the Civil Rights Act of 1964, the creation of Martin Luther King Jr. Day, and developed the reform of lobbying. His time as the chairman of the Senate Budget Committee from 1975 to 1980 include the formation of the United States budget process. Because of this, he is known as the "father of the federal budget process". David Broder of The Washington Post, noted that Muskie's leadership of the Senate's intergovernmental relations subcommittee was, in part, responsible for countering Richard Nixon's "Imperial Presidency" and advancing "New Federalism".

Alongside President Johnson's Great Society and War on Poverty programs, Muskie drafted the Model Cities Bill which eventually passed both houses of Congress in 1966. Previously, combative with Johnson, Muskie began developing a more cooperative relationship with him. During Johnson's signing of the Intergovernmental Cooperation Act he said: I am pleased that Senator Muskie could be with us this afternoon. I believe that no man has done more to encourage cooperation among the National Government, the States, and the cities." Also in 1966, Muskie was elected assistant Democratic whip and served as the floor manager for the Clean Water Restoration Act.

During 1967 the popular sentiment in the U.S. was anti-war, which prompted Muskie to visit Vietnam to inform his political stance in 1968. Prior to his visiting the country, he debated with a congressman on a pro-war platform. After the trip, he became a leading voice for the movement and entered into the ongoing debate by speaking at the year's Democratic Convention. His speech was followed by "tens of thousands of protestors surrounded the convention and violent clashes with police carried on for five days." He wrote to Johnson personally asserting his position on the Vietnam War. He made the case that the U.S. ought to withdraw from Vietnam as quickly as possible. Months later, he wrote to the President again urging him to end the bombing of North Vietnam. During the same year, he traveled with other Senators to the Republic of South Vietnam to validate their elections.

At the conclusion of his political career, he held the highest political office by a Polish American in U.S. history, and also was the only Polish American ever nominated by a major party for vice President. On the 100th birthday of Edmund Muskie, U.S. Senator Agnus King spoke on the floor of the United States Senate in memoriam. King noted the following: "if you would see Ed Muskie's memorial, look around you. Take a deep breath. Experience our great rivers. Experience the environment that we now have in the country that we treasure." Muskie has received the keys to all three major cities in Maine: Portland, Lewiston, and Augusta. He was given honorary citizenship to the State of Texas in 1968. Numerous days have been named "Edmund S. Muskie Day": September 25, 1968 (Michigan), January 20, 1980 (New York), March 28, 1988 (Maine), March 1928, 1994 (Maine), and March 20, 1995 (Maine). In 1987, the Maine State Legislature enacted Statute §A7 enacting "Edmund S. Muskie Day" on March 28. The statute was amended in 1989; Edmund S. Muskie Day is celebrated annually and is a public holiday in Maine.

Before the 1972 election, Muskie was viewed as a front-runner for the Democratic presidential nomination. Despite his political rise in the polls he continued to engage in tiring day after day speeches in various part of the country. During an August 17, 1969 appearance on Meet the Press, Muskie said his entry into the presidential primary would depend on his being convinced that he could meet the challenges as well as his comfort: "I don't think I'll answer either question for a year or two." On November 8, 1970, Muskie said he would only declare himself as a presidential candidate in the event he became convinced he was best suited for the unifying the country through the presidency. In August 1971, Harris polling amid a growing economic crisis, Muskie came out on top of incumbent Nixon if the election had been held that day. In late 1971, Muskie gave an anti-war speech in Providence. The nation was at war in Vietnam and President Richard Nixon's foreign policy promised to be a major issue in the campaign.

His third term began in 1970 by co-sponsoring the McGovern-Hatfield resolution to limit military intervention in the Vietnam War. During this time Harold Carswell was seeking appointment to the U.S. Supreme Court. Muskie voted against him and Carswell failed the confirmation process. Muskie also proposed a six-month ban on domestic and Soviet Union development of nuclear technologies to taper the nuclear arms race.

He co-wrote amendments to the Federal Water Pollution Act, more commonly known as the Clean Water Act, on October 28, 1971 in order to mitigate the "disproportionately high and adverse human health or environmental effects of its programs, policies, and activities on minority, low-income, and indigenous populations." The bill enjoyed bipartisan support in the U.S. Congress and was passed by the lower house on November 29, 1971 and the upper house on March 29, 1972. While congressional support was enough to enact it into law President Richard Nixon exercised his executive veto on the bill and stopped it from becoming law. However, after further campaigning by Muskie, the Senate and House of Representatives passed the bill 247-23 to override Nixon's veto. The bill was historic in that it established the regulation of pollutants in the federal and state waters of the U.S., created extended authority for the Environmental Protection Agency, and created water health standards. Also in 1971, Muskie was asked to join the Senate Foreign Relations Committee; he traveled to Europe and the Middle East in this capacity.

Evidence later came to light during the Watergate scandal investigation that, during the 1972 presidential campaign, the Nixon campaign committee maintained a "dirty tricks" unit focused on discrediting Nixon's strongest challengers. Federal Bureau of Investigation (FBI) investigators revealed that the Canuck Letter was a forged document as part of the dirty-tricks campaign against Democrats orchestrated by the Nixon campaign. Nixon was also reported to have ordered men to follow Muskie around and gather information. He tried to connect Muskie's acquaintance with singer Frank Sinatra to an abuse of office. Muskie often flew on Sinatra's private plane while traveling around California.

He served as the chairman of the Senate Budget Committee through the Ninety-third to the Ninety-sixth Congresses from 1973 to 1980. During this time, Congress founded the Congressional Budget Office in order to challenge Nixon's budget request. Prior to 1974, there was no formal process for establishing a federal budget so Congress founded the office under the auspices of the Senate Budget Committee. As chairman, Muskie presided over, formulated, and approved of the creation of the United States budget process.

In early July 1976, Muskie spoke with Jimmy Carter in a "productive" and "harmonious" discussion that was followed by Carter confirming that he considered Muskie qualified for the vice-presidential nomination. Carter ultimately selected Walter Mondale as his running mate.

In 1977, he amended Federal Water Pollution Control Act of 1972 along with others, to pass the Clean Water Act of 1977. These new additions incorporated "non-degradation" or "clean growth" policies intended to limit negative externalities. In 1978, he made minor adjustments to the Resource Conservation and Recovery Act and the "Superfund".

Muskie's influence on American diplomacy was detailed by the Office of the Historian with the following: "In the nine months Muskie served as Secretary of State, he conducted the first high-level meeting with the Soviet government after its December 1979 invasion of Afghanistan. During these negotiations, Secretary Muskie unsuccessfully attempted to secure the withdrawal of Soviet forces from Afghanistan. [He] also assisted President Carter in the implementation of the "Carter Doctrine," which aimed to limit Soviet expansion into the Middle East and Persian Gulf. Finally, under Muskie’s leadership, the State Department negotiated the release of the remaining American hostages held by Iran." Many political commentators believed the bestowing of the Presidential Medal of Freedom by Carter to be an affirmation of this assertion.

In June 1980, there was a "draft Muskie" movement among Democratic voters within the primaries of the 1980 presidential election. President Carter was running against Senator Ted Kennedy, and opinion polls ranked Muskie more favorably against Kennedy. One poll showed that Muskie would be a more popular alternative to Carter than Ted Kennedy, implying that the attraction was not so much to Kennedy as to the fact that he was not Carter. Moreover, Muskie was polled against Republican challenger Ronald Reagan at the time showing Carter seven points down. Due to a political allegiance with Carter, he backed out of the contention. Pressured by the Carter Administration, Muskie released the following public statement to Democratic voters: "I accepted the appointment as secretary of state to serve the country and to serve the President. I continue to serve the President, and I will support him all the way! I have a commitment to the President. I don't make such commitments lightly, and I intend to keep it." An article by The New Yorker speculated that the move to back Muskie was a temporary flex of political power by the Democratic voter base to unease Carter.

Muskie was awarded the Presidential Medal of Freedom–the nation's highest honor–by President Jimmy Carter on January 16, 1981 for his work during the Iran hostage crisis, four days before stepping down from the presidency. In 1984, the House of Representatives designated the Edmund S. Muskie Federal Building in Augusta.

In 1987, as an elder statesman, Muskie was appointed a member of the President's Special Review Board known as the "Tower Commission" to investigate President Ronald Reagan's administration's role in the Iran-Contra affair. Muskie and the commission issued a highly detailed report of more than 300 pages that was critical of the Presidents actions and blamed the White House chief of staff, Donald T. Regan, for unduly influencing the president's activities. The panel was notable as the findings of the report was directly critical of the President who appointed the commission.

The Edmund S. Muskie School of Public Service at the University of Southern Maine was named in his honor in 1990. Muskie's papers and personal effects are kept at the Edmund S. Muskie Archives and Special Collections Library at Bates College in Lewiston, Maine.

The American Bar Association honors lawyers who under take pro bono work with the annual Edmund S. Muskie Pro Bono Service Award. From 1993 to 2013, the United State Department of State ran the Edmund S. Muskie Graduate Fellowship Program in an effort to increase international study abroad. In 1996, the Edmund S. Muskie Distinguished Public Service Award was founded by the Truman National SecurityProject to honor current or former elected officials.

Muskie was memorialized in Washington D.C., Lewiston, Maine, and Bethesda, Maryland. At his Washington memorial, he was paid tribute to by a variety of U.S. senators and house representatives. His alma mater–Bates College–held a memorial presided over by its President, Donald Harward. On March 30, 1996, a publicly-broadcast, Roman Catholic funeral was held in Bethesda at the Church of the Little Flower. He was eulogized by U.S. President Jimmy Carter; U.S. Senator, George J. Mitchell; 20th United States Ambassador to the United Nations, Madeleine Albright; a political aide, Leon G. Billings; and one of Muskie's sons, Stephen.

Due to his Service in the United States Naval Reserve during World War II, he was eligible to be buried at Arlington National Cemetery in Arlington County, Virginia. His ultimate rank of lieutenant had him placed in Section 25 of the cemetery. Although he died on March 26, his grave stone initially noted that he died on the 25th. His wife, Jane, died on December 25, 2004, due to health complications brought on by Alzheimer's disease. She was buried next to Muskie and his grave stone was corrected to read "March 26, 1996".

Historical evaluations of Edmund Muskie focus on the impact his actions and legislation had in the United States and the greater world. His accomplishments in his home state have had him noted as one of the most influential politicians in the history of Maine. Depending on the metric he is coupled with Hannibal Hamlin and James Blaine as the three most important politicians from Maine. Muskie occupied all offices available in the Maine political system excluding state senator and United States representative. His political status in Maine is generally perceived favorably. During his four-year term as Governor of Maine he initiated a constitutional amendment, invested heavily in infrastructure, and institutionalized economic development– effectively bringing Maine into the Golden Age of Capitalism. Muskie ended the "as Maine goes, so goes the nation" political sentiment in the United States by moving Maine's general election date to November instead of September. He preserved the cultural integrity of the state by endowing the Maine State Museum which was seen as critical to his public perception. Although economic expansionism was historically seen negatively by the people of Maine, Muskie's policies were seen favorably as they were coupled with environmental provisions. His advocation for minimum wage increases, increased labor protections, and sales tax exemptions boosted consumer spending. Muskie has been widely characterized as the catalyst for the political renaissance of the Democratic Party in Maine. His election to the governorship signaled a fracturing of the Republican Party in the state and nearly tripled the amount of Democrats in Maine between 1954 and 1974.