Billy Sunday was born near Ames, Iowa. His Father was the son of German immigrants named Sonntag, who anglicized their name to "Sunday" when they settled in Chambersburg, Pennsylvania. william Sunday was a bricklayer who worked his way to Iowa, where he married Mary Jane Corey, daughter of "Squire" Martin Corey, a local farmer, miller, blacksmith, and wheelwright. william Sunday enlisted in the Iowa Twenty-Third Volunteer Infantry on August 14, 1862. He died four months later of pneumonia at an army camp in Patterson, Missouri, five weeks after the birth of his youngest son, william Ashley. Mary Jane Sunday and her children moved in with her parents for a few years, and young Billy became close to his grandparents and especially his grandmother. Mary Jane Sunday later remarried, but her second husband soon deserted the family.

In 1880, Sunday relocated to Marshalltown, Iowa, where, because of his athleticism, he had been recruited for a fire brigade team. In Marshalltown, Sunday worked at odd jobs, competed in fire brigade tournaments, and played for the town baseball team. In 1882, with Sunday in left field, the Marshalltown team defeated the state champion Des Moines team 13–4.

Sunday's professional baseball career was launched by Adrian "Cap" Anson, a Marshalltown native and Future Hall of Famer, after his aunt, an avid fan of the Marshalltown team, gave him an enthusiastic account of Sunday's prowess. In 1883, on Anson's recommendation, A.G. Spalding, President of the Chicago White Stockings, signed Sunday to the defending National League champions.

Sunday's speed was his greatest asset, and he displayed it both on the basepaths and in the outfield. In 1885, the White Stockings arranged a race between Sunday and Arlie Latham, the fastest Runner in the American Association. Sunday won the hundred-yard dash by about ten feet.

On a Sunday afternoon in Chicago, during either the 1886 or 1887 baseball season, Sunday and several of his teammates were out on the town on their day off. At one street corner, they stopped to Listen to a gospel preaching team from the Pacific Garden Mission. Attracted by the hymns he had heard his mother sing, Sunday began attending services at the mission. After talking with a former society matron who worked there, Sunday – after some struggle on his part – decided to become a Christian. He began attending the fashionable Jefferson Park Presbyterian Church, a congregation handy to both the ball park and his rented room.

In 1887, when Kelly was sold to another team, Sunday became Chicago's regular right fielder, but an injury limited his playing time to fifty games. During the following winter Sunday was sold to the Pittsburgh Alleghenys for the 1888 season. He was their starting center fielder, playing a full season for the first time in his career. The crowds in Pittsburgh took to Sunday immediately; one reporter wrote that "the whole town is wild over Sunday." Although Pittsburgh had a losing team during the 1888 and 1889 seasons, Sunday performed well in center field and was among the league Leaders in stolen bases.

In 1886, Sunday was introduced at Jefferson Park Presbyterian Church to Helen Amelia "Nell" Thompson, daughter of the owner of one of Chicago's largest dairy products businesses. Although Sunday was immediately smitten with her, both had serious on-going relationships that bordered on engagements. Furthermore, Nell Thompson had grown to maturity in a much more privileged environment than had Sunday, and her Father strongly discouraged the courtship, viewing all professional baseball players as "transient ne'er-do-wells who were unstable and destined to be misfits once they were too old to play." Nevertheless, Sunday pursued and eventually married her. On several occasions, Sunday said, "She was a Presbyterian, so I am a Presbyterian. Had she been a Catholic, I would have been a Catholic – because I was hot on the trail of Nell." Mrs. Thompson had liked Sunday from the start and weighed in on his side, and Mr. Thompson finally relented. The couple was married on September 5, 1888.

In 1890, a labor dispute led to the formation of a new league, composed of most of the better players from the National League. Although he was invited to join the competing league, Sunday's conscience would not allow him to break his contract with Pittsburgh. Sunday was named team captain, and he was their star player, but the team suffered one of the worst seasons in baseball history. By August the team had no money to meet its payroll, and Sunday was traded to the Philadelphia Phillies for two players and $1,000 in cash.

In the spring of 1891, Sunday turned down a baseball contract for $3,500 a year to accept a position with the Chicago YMCA at $83 per month. Sunday's job title at the YMCA was Assistant Secretary, yet the position involved a great deal of ministerial work. It proved to be good preparation for his later evangelistic career. For three years Sunday visited the sick, prayed with the troubled, counseled the suicidal, and visited saloons to invite patrons to evangelistic meetings.

In 1893, Sunday became the full-time assistant to J. Wilbur Chapman, one of the best known Evangelists in the United States at the time. Chapman was well educated and was a meticulous dresser, "suave and urbane." Personally shy, like Sunday, Chapman commanded respect in the pulpit both because of his strong voice and his sophisticated demeanor. Sunday's job as Chapman's advance man was to precede the evangelist to cities in which he was scheduled to preach, organize prayer meetings and choirs, and in general take care of necessary details. When tents were used, Sunday would often help erect them.

When Chapman unexpectedly returned to the pastorate in 1896, Sunday struck out on his own, beginning with meetings in tiny Garner, Iowa. For the next twelve years Sunday preached in approximately seventy communities, most of them in Iowa and Illinois. Sunday referred to these towns as the "kerosene circuit" because, unlike Chicago, most were not yet electrified. Towns often booked Sunday meetings informally, sometimes by sending a delegation to hear him preach and then telegraphing him while he was holding services somewhere else.

Although Sunday was ordained by the Presbyterian Church in 1903, his ministry was nondenominational and he was not a strict Calvinist. He preached that individuals were, at least in part, responsible for their own salvation. "Trail hitters" were given a four-page tract that stated, "if you have done your part (i.e. believe that Christ died in your place, and receive Him as your Saviour and Master) God has done HIS part and imparted to you His own nature."

When Sunday began to attract crowds larger than could be accommodated in rural churches or town halls, he pitched rented canvas tents. Again, Sunday did much of the physical work of putting them up, manipulating ropes during storms, and seeing to their security by sleeping in them at night. Not until 1905 was he well-off enough to hire his own advance man.

In 1906, an October snowstorm in Salida, Colorado, destroyed Sunday's tent – a special disaster because revivalists were typically paid with a freewill offering at the end of their meetings. Thereafter he insisted that towns build him temporary wooden tabernacles at their expense. The tabernacles were comparatively costly to build (although most of the lumber could be salvaged and resold at the end of the meetings), and locals had to put up the money for them in advance. This change in Sunday's operation began to push the finances of the campaign to the fore. At least at first, raising tabernacles provided good public relations for the coming meetings as townspeople joined together in what was effectively a giant barnraising. Sunday built rapport by participating in the process, and the tabernacles were also a status symbol, because they had previously been built only for major Evangelists such as Chapman.

In 1907, Journalist Lindsay Denison complained that Sunday preached "the old, old doctrine of damnation". Denison wrote, "In spite of his conviction that the truly religious man should take his religion joyfully, he gets his results by inspiring fear and gloom in the hearts of sinners. The fear of death, with torment beyond it—intensified by examples of the frightful deathbeds of those who have carelessly or obdurately put off salvation until it is too late—it is with this mighty menace that he drives sinners into the fold." But Sunday himself told reporters "with ill-concealed annoyance" that his revivals had "no emotionalism." Certainly contemporary comparisons to the extravagances of mid-nineteenth-century camp meetings—as in the famous drawing by George Bellows—were overdrawn. Sunday told one reporter that he believed that people could "be converted without any fuss," and, at Sunday's meetings, "instances of spasm, shakes, or fainting fits caused by hysteria were few and far between."

Eleven years into Sunday's evangelistic career, both he and his wife had been pushed to their emotional limits. Long separations had exacerbated his natural feelings of inadequacy and insecurity. As a product of a childhood that could well be described as a series of losses, he was extremely dependent on his wife's love and encouragement. For her part, Nell found it increasingly difficult to handle household responsibilities, the needs of four children (including a newborn), and the long-distance emotional welfare of her husband. His ministry was also expanding, and he needed an administrator, a job for which his wife was ideally suited. In 1908, the Sundays decided to entrust their children to a nanny so that Nell could manage the revival campaigns.

The Sundays enjoyed dressing well and dressing their children well; the family sported expensive but tasteful coats, boots, and jewelry. Nell Sunday also bought land as an investment. In 1909, the Sundays bought an apple orchard in Hood River, Oregon, where they vacationed for several years. Although the property sported only a rustic cabin, reporters called it a "ranch." Sunday was a soft touch with money and gave away much of his earnings. Neither of the Sundays were extravagant spenders. Although Sunday enjoyed driving, the couple never owned a car. In 1911, the Sundays moved to Winona Lake, Indiana, and built an American Craftsman-style bungalow, which they called "Mount Hood", probably as a reminder of their Oregon vacation cabin. The bungalow, furnished in the popular Arts and Crafts style, had two porches and a terraced garden but only nine rooms, 2,500 square feet (230 m) of living space, and no garage.

By 1910, Sunday began to conduct meetings (usually longer than a month) in small cities like Youngstown, Wilkes-Barre, South Bend, and Denver, and then finally, between 1915 and 1917, the major cities of Philadelphia, Syracuse, Kansas City, Detroit, Boston, Buffalo, and New York City. During the 1910s, Sunday was front-page news in the cities where he held campaigns. Newspapers often printed his sermons in full, and during World War I, local coverage of his campaigns often surpassed that of the war. Sunday was the subject of over sixty articles in major periodicals, and he was a staple of the religious press regardless of denomination.

Large crowds and an efficient organization meant that Sunday, the former resident of an orphan home, was soon netting hefty offerings. The first questions about Sunday's income were apparently raised during the Columbus, Ohio, campaign at the turn of 1912–13. During the Pittsburgh campaign a year later, Sunday spoke four times per day and effectively made $217 per sermon or $870 a day at a time when the average gainfully employed worker made $836 per year. The major cities of Chicago, Philadelphia, Baltimore, Boston, and New York City gave Sunday even larger offerings. Sunday donated Chicago's offering of $58,000 to Pacific Garden Mission and the $120,500 New York offering to war charities. Nevertheless, between 1908 and 1920, the Sundays earned over a million dollars; an average worker during the same period earned less than $14,000.

Sunday was not a separationist as were many Protestants of his era. He went out of his way to avoid criticizing the Roman Catholic Church and even met with Cardinal Gibbons during his 1916 Baltimore campaign. Also, cards filled out by "trail hitters" were faithfully returned to the church or denomination that the Writers had indicated as their choice, including Catholic and Unitarian.

Sunday was welcomed into the circle of the social, economic, and political elite. He counted among his neighbors and acquaintances several prominent businessmen. Sunday dined with numerous politicians, including Presidents Theodore Roosevelt and Woodrow Wilson, and counted both Herbert Hoover and John D. Rockefeller, Jr. as friends. During and after the 1917 Los Angeles campaign, the Sundays visited with Hollywood stars, and members of Sunday's organization played a charity baseball game against a team of show Business personalities that included Douglas Fairbanks, Sr.

Sunday was a passionate supporter of World War I. In 1918 he said, "I tell you it is [Kaiser] Bill against Woodrow, Germany against America, Hell against Heaven." Sunday raised large amounts of money for the troops, sold war bonds, and stumped for recruitment.

Sunday had been an ardent champion of temperance from his earliest days as an evangelist, and his ministry at the Chicago YMCA had given him first-hand experience with the destructive potential of alcohol. Sunday's most famous sermon was "Get on the Water Wagon", which he preached on countless occasions with both histrionic emotion and a "mountain of economic and moral evidence." Sunday said, "I am the sworn, eternal and uncompromising enemy of the Liquor Traffic. I have been, and will go on, fighting that damnable, dirty, rotten Business with all the power at my command." Sunday played a significant role in arousing public interest in Prohibition and in the passage of the Eighteenth Amendment in 1919. When the tide of public opinion turned against Prohibition, he continued to support it. After its repeal in 1933, Sunday called for its reintroduction.

Sunday was a lifelong Republican, and he espoused the mainstream political and social views of his native Midwest: individualism, competitiveness, personal discipline, and opposition to government regulation. Writers such as Sinclair Lewis, Henry M. Tichenor, and John Reed attacked Sunday as a tool of big Business, and poet Carl Sandburg called him a "four-flusher" and a "bunkshooter." Nevertheless, Sunday sided with Progressives on some issues. For Example, he denounced child labor and supported urban reform and women's suffrage. Sunday condemned capitalists "whose private lives are good, but whose public lives are very bad", as well as those "who would not pick the pockets of one man with the fingers of their hand" but who would "without hesitation pick the pockets of eighty million people with fingers of their monopoly or commercial advantage." He never lost his sympathy for the poor, and he sincerely tried to bridge the gulf between the races during the zenith of the Jim Crow era, although on at least two occasions in the mid-1920s Sunday received contributions from the Ku Klux Klan.

Tragedy marred Sunday's final years. His three sons engaged in many of the activities he preached against, and the Sundays paid blackmail to several women to keep the scandals relatively quiet. In 1930, Nora Lynn, their housekeeper and nanny, who had become a virtual member of the family, died. Then the Sundays' daughter, the only child actually raised by Nell, died in 1932 of what seems to have been multiple sclerosis. Their oldest son George, rescued from financial ruin by his parents, committed suicide in 1933.

Nevertheless, even as the crowds declined during the last 15 years of his life, Sunday continued accepting preaching invitations and speaking with effect. In early 1935, he had a mild heart attack, and his Doctor advised him to stay out of the pulpit. Sunday ignored the advice. He died on November 6, a week after preaching his last sermon on the text "What must I do to be saved?"

Sunday's popularity waned after World War I, when many people in his revival audiences were attracted to radio broadcasts and moving pictures instead. The Sundays' health also declined even as they continued to drive themselves through rounds of revivals—smaller but also with fewer staff members to assist them.