At the 58th Annual Grammy Awards in February, the Eagles, joined by Leadon, touring Guitarist Steuart Smith, and co-writer Jackson Browne, performed "Take It Easy" in honor of Frey. In subsequent interviews, Henley stated that he didn't think the band would perform again.

Influenced by 1960s rhythm and blues, soul, bluegrass, and rock bands such as the Byrds and Buffalo Springfield, the Eagles' overall sound has been described as "California rock." In the words of Sal Manna, author of the CD liner notes of the band's 1994 album Hell Freezes Over, "no one knew quite what 'California rock' meant – except perhaps that, because in California anything was possible, music that came from that promising land was more free-spirited and free-ranging." Rolling Stone described the Eagles' sound as "country-tinged vocal harmonies with hard rock guitars and lyrics."

After the Eagles broke up, the former members pursued solo careers. Elektra, the band's long-time record label, owned the rights to solo albums created by members of the Eagles (though several of them moved to different labels in ensuing years). Walsh had established himself as a solo Artist in the 1970s, before and during his time with the Eagles, but it was uncharted waters for the others. Walsh released a successful album in 1981, There Goes the Neighborhood, but subsequent albums throughout the 1980s, such as Got Any Gum? were less well received. During this period Walsh performed as a session musician for Dan Fogelberg, Steve Winwood, John Entwistle, Richard Marx and Emerson, Lake & Palmer, among others, and produced and co-wrote Ringo Starr's Old Wave album.

While on the tour, Frey and Henley decided to form a band together and informed Ronstadt of their intention. Frey later credited Ronstadt with suggesting Leadon for the band, and arranging for Leadon to play for her so Frey and Henley could approach him about forming a band together. They also pitched the idea to Meisner and brought him on board. These four played live together behind Ronstadt only once for a July concert at Disneyland, but all four appeared on her eponymous album. It was later proposed that J. D. Souther should join the band, but Meisner objected. The four were signed in September 1971 to Asylum Records, the new label started by David Geffen, who was introduced to Frey by Jackson Browne. Geffen bought out Frey's and Henley's contracts with Amos Records, and sent the four to Aspen, Colorado to develop as a band. Having not settled on a band name yet, they performed their first show in October 1971 under the name of Teen King and the Emergencies at a club called The Gallery in Aspen. Don Felder credited Leadon with originating the name of Eagles for the band during a peyote and tequila-influenced group outing in the Mojave Desert, when he recalled reading about the Hopis' reverence for the eagle. Accounts however vary, and J.D. Souther suggested that the idea came when Frey shouted out, "Eagles!" when they saw eagles flying above. Steve Martin, a friend of the band from their early days at The Troubadour, recounts in his autobiography that he suggested that they should be referred to as "the Eagles," but Frey insists that the group's name is simply "Eagles." Geffen and partner Elliot Roberts initially managed the band; they were later replaced by Irving Azoff while the Eagles were recording their third album.

The group's eponymous debut album was recorded in England in February 1972 with Producer Glyn Johns. Johns was impressed by the harmony singing of the band, and he has been credited with shaping the band into "the country-rock band with those high-flyin' harmonies." Released on June 1, 1972, Eagles was a breakthrough success, yielding three Top 40 singles. The first single and lead track, "Take It Easy," was a song written by Frey with his then-neighbor and fellow country-folk rocker Jackson Browne. Browne had written the first verse of the song, but got stalled on the second verse after the line "I'm standing on a corner in Winslow, Arizona." Frey completed the verse with "It's a girl, my Lord, in a flatbed Ford, slowin' down to take a look at me," and Browne carried on to finish the song. The song reached number 12 on the Billboard Hot 100 and propelled the Eagles to stardom. The single was followed by the bluesy "Witchy Woman" and the soft country rock ballad "Peaceful Easy Feeling," charting at number 9 and number 22 respectively. The group supported the album with a US tour as the opening act for Yes.

The band played at the California Jam festival in Ontario, California on April 6, 1974. Attracting more than 300,000 fans and billed as "the Woodstock of the West Coast," the festival featured Black Sabbath, Emerson, Lake & Palmer, Deep Purple, Earth, Wind & Fire, Seals & Crofts, Black Oak Arkansas, and Rare Earth. Portions of the show were telecast on ABC television in the United States, exposing the Eagles to a wider audience. Felder missed the show when he was called away to attend the birth of his son; Jackson Browne filled in for him on piano and acoustic guitar.

On their early records, the group combined rock and roll, country, and folk music styles. For their third album On the Border, the band widened their style to include a prominent hard rock sound, a genre the band had only touched upon previously. The 1975 follow-up album One of These Nights saw the group explore a softer sound, notably exemplified on the hit singles "Take It to the Limit," and "Lyin' Eyes. Leadon, who was the principal country influence, left the band after the album was released, and the band moved away from country rock to a more rock direction in Hotel California. The band's 2007 comeback album Long Road Out of Eden saw them explore country rock, blues rock, and funk.

The following album, Hotel California, released on December 8, 1976, was the band's fifth studio album and the first to feature Walsh. The album took a year and a half to complete, a process which, along with touring, drained the band. The album's first single, "New Kid in Town," became the Eagles' third number-one single.

In 1977, the group, minus Don Felder, performed instrumental work and backing vocals for Randy Newman's album Little Criminals, including "Short People," which has backup vocals by Frey and Schmit.

The album won Grammys for "Record of the Year" ("Hotel California") and "Best Arrangement for Voices" ("New Kid in Town"). Hotel California topped the charts and was nominated for Album of the Year at the 1978 Grammy Awards, but lost to Fleetwood Mac's Rumours. The huge worldwide tour in support of the album further drained the band members and strained their personal and creative relationships.

The Eagles went into the recording studio in 1977 to begin work on their next album, The Long Run. The album took two years to complete. It was originally intended to be a double album, but the band members were unable to write enough songs. The Long Run was released on September 24, 1979. Considered a disappointment by some critics for failing to live up to Hotel California, it proved a huge commercial hit nonetheless; the album topped the charts and sold seven million copies. In addition, it included three Top 10 singles. "Heartache Tonight" became their last single to top the Hot 100, on November 10, 1979. The title track and "I Can't Tell You Why" both reached number 8. The band won their fourth Grammy for "Heartache Tonight." "In The City" by Walsh and "The Sad Cafe" became live staples. The band also recorded two Christmas songs during these sessions, "Funky New Year" and "Please Come Home for Christmas," which was released as a single in 1978 and reached number 18 on the charts.

Frey also achieved solo success in the 1980s. In 1982, he released his first album, No Fun Aloud, which spawned the number 15 hit, "The One You Love." The Allnighter (1984) featured the number 20 hit "Sexy Girl." He reached number 2 on the charts with "The Heat Is On" from the Beverly Hills Cop Soundtrack. He had another number 2 single in 1985 with "You Belong to the City" from the Miami Vice Soundtrack, which featured another Frey song, "Smuggler's Blues." He appeared as "Jimmy" in the episode titled after the song and contributed riffs to the episode's Soundtrack. He also contributed the songs "Flip City" to the Ghostbusters II Soundtrack and "Part of Me, Part of You" to the Soundtrack for Thelma & Louise.

Meisner hit the top 40 three times, including the number 19 "Hearts on Fire" in 1981.

Schmit had a prolific solo career after the band's initial breakup. He had a hit song on the Fast Times at Ridgemont High Soundtrack with "So Much in Love." He contributed vocals to the Crosby, Stills & Nash album Daylight Again on the songs "Southern Cross" and "Wasted on the Way" when that band needed an extra vocalist due to David Crosby's drug overindulgence. Schmit sang backup vocals on Toto's Toto IV album, including the song "I Won't Hold You Back" and appeared with the group on their 1982 European tour. He spent three years (1983–1985) as a member of Jimmy Buffett's Coral Reefer band and coined the term "Parrotheads" for Buffett's die-hard fans. He had a Top 40 solo hit in 1987 with "Boys' Night Out" and a top-30 Adult Contemporary hit with "Don't Give Up," both from his album Timothy B. Schmit appeared with Meisner and Walsh on Richard Marx's debut single "Don't Mean Nothing." In 1992, Schmit and Walsh toured as members of Ringo Starr's All-Starr Band and appeared on the live video from the Montreux Jazz Festival. Schmit released two solo albums, Playin' It Cool in 1984 and Tell Me the Truth in 1990. He was the only Eagle to appear on the 1993 Eagles tribute album Common Thread: The Songs of the Eagles, singing backing vocals on Vince Gill's cover of "I Can't Tell You Why."

An Eagles country tribute album, titled Common Thread: The Songs of the Eagles, was released in 1993, 13 years after the breakup. Travis Tritt insisted on having the Long Run-era Eagles in his video for "Take It Easy" and they agreed. Following years of public speculation, the band formally reunited the following year. The lineup comprised the five Long Run-era members—Frey, Henley, Walsh, Felder, and Schmit—supplemented by Scott Crago (drums), John Corey (keyboards, guitar, backing vocals), Timothy Drury (keyboards, guitar, backing vocals), and former Loggins and Messina sideman Al Garth (sax, violin) on stage.

"For the record, we never broke up, we just took a 14-year vacation," announced Frey at their first live performance in April 1994. The ensuing tour spawned a live album titled Hell Freezes Over (named for Henley's recurring statement that the group would get back together "when hell freezes over"), which debuted at number 1 on the Billboard album chart. It included four new studio songs, with "Get Over It" and "Love Will Keep Us Alive" both becoming Top 40 hits. The album proved as successful as the tour, selling six million copies in the U.S. The tour was interrupted in September 1994 because of Frey's serious recurrence of diverticulitis, but it resumed in 1995 and continued into 1996. In 1998, the Eagles were inducted into the Rock and Roll Hall of Fame. For the induction ceremony, all seven Eagles members (Frey, Henley, Felder, Walsh, Schmit, Leadon, and Meisner) played together for two songs, "Take It Easy" and "Hotel California." Several subsequent reunion tours followed (without Leadon or Meisner), notable for their record-setting ticket prices.

The Eagles performed at the Mandalay Bay Events Center in Las Vegas on December 28 and 29, 1999, followed by a concert at the Staples Center in Los Angeles on December 31. These concerts marked the last time Felder played with the band and the shows (including a planned video release) would later form a part of a lawsuit filed by Felder against his former band mates. The concert recordings were released on CD as part of the four-disc Selected Works: 1972–1999 box set in November 2000. Along with the concert, this set included the band's hit singles, album tracks and outtakes from The Long Run sessions. Selected Works received platinum certification from the Recording Industry Association of America (RIAA) in 2002. The group resumed touring in 2001, with a line-up consisting of Frey, Henley, Walsh, and Schmit, along with Steuart Smith (guitars, mandolin, keyboards, backing vocals; essentially taking over Felder's role), Michael Thompson (keyboards, trombone), Will Hollis (keyboards, backing vocals), Scott Crago (drums, percussion), Bill Armstrong (Horns), Al Garth (sax, violin), Christian Mostert (sax), and Greg Smith (sax, percussion).

On February 6, 2001, Don Felder was fired from the Eagles. He responded by filing two lawsuits against "Eagles, Ltd.," a California corporation; Don Henley, an individual; Glenn Frey, an individual; and "Does 1–50," alleging wrongful termination, breach of implied-in-fact contract and breach of fiduciary duty, reportedly seeking $50 million in damages. Felder alleged that from the 1994 Hell Freezes Over tour onward, Henley and Frey had .".. insisted that they each receive a higher percentage of the band's profits ...," whereas the money had previously been split in five equal portions. Felder accused them of coercing him into signing an agreement under which Henley and Frey would receive three times as much of the Selected Works: 1972–1999 proceeds.

On January 23, 2002, the Los Angeles County Court consolidated the two complaints, set a trial date for September 2006, and the single case was dismissed on May 8, 2007, after being settled out of court for an undisclosed amount.

In 2003, the Eagles released a greatest hits album, The Very Best Of. The two-disc compilation was the first that encompassed their entire career from Eagles to Hell Freezes Over. It debuted at number 3 on the Billboard charts and eventually gained triple platinum status. The album included a new single, the September 11 attacks-themed "Hole in the World." Also in 2003, Warren Zevon, a longtime Eagles friend, began work on his final album, The Wind, with the assistance of Henley, Walsh, and Schmit.

On June 14, 2005, the Eagles released a new 2-DVD set, Farewell 1 Tour-Live from Melbourne, featuring two new songs: Frey's "No More Cloudy Days" and Walsh's "One Day at a Time." A special edition 2006 release, exclusive to Walmart and affiliated stores, includes a bonus audio CD with three new songs: a studio version of "No More Cloudy Days," "Fast Company," and "Do Something."

The Eagles made their awards show debut on November 7, 2007, when they performed "How Long" live at the Country Music Association Awards.

On March 20, 2008, the Eagles launched their world tour in support of Long Road Out of Eden at The O2 Arena in London. The Long Road Out of Eden Tour concluded the American portion of the tour at Rio Tinto Stadium in Sandy, Utah on May 9, 2009. It was the first concert ever held in the new soccer stadium. The tour travelled to Europe, with its final concert date on July 22, 2009, in Lisbon. The band spent the summer of 2010 touring North American stadiums with the Dixie Chicks and Keith Urban. The tour expanded to England as the headline act of the Hop Farm Festival on July 1, 2011.

Asked in November 2010 whether the Eagles were planning a follow-up to Long Road Out of Eden, Schmit replied, "My first reaction would be: no way. But I said that before the last one, so you never really know. Bands are a fragile entity and you never know what's going to happen. It took a long time to do that last album, over a span of years, really, and it took a lot out of us. We took a year off at one point. I'm not sure if we're able to do that again. I wouldn't close the door on it, but I don't know." Walsh said in 2010 that there might be one more album before the band "wraps it up." Frey later stated in a 2012 interview that the band has had discussions about releasing an EP of potentially 4–6 songs that may contain both original and cover material.

In February 2013, the Eagles released a career-spanning documentary called History of the Eagles and began the supporting tour with 11 US arena concerts in July. Henley said that the tour, which expanded internationally and continued until July 2015, "could very well be our last...we're gonna include at least one former band member in this tour and kinda go back to the roots, and how we created some of these songs. We're gonna break it down to the fundamentals and then take it up to where it is now." Original Eagles Guitarist Bernie Leadon also appeared on the tour. Walsh stated, "Bernie’s brilliant, I never really got a chance to play with him, but we've been in contact. We see him from time to time, and I'm really glad he's coming because it's going to take the show up a notch, and I'm really looking forward to playing with him, finally." Former members Randy Meisner and Don Felder did not appear. Meisner had been invited but could not participate for health reasons, while Felder was never asked. Though his lawsuits against the Eagles were settled in 2007, Henley claimed that Felder continued to "engage in legal action, of one kind or another" against the band, but did not state what those actions were.

The Eagles are one of the world's best-selling bands in history, having sold more than 150 million records—100 million in the U.S. alone—including 42 million copies of Their Greatest Hits (1971–1975) and 32 million copies of Hotel California. Their Greatest Hits (1971–1975) was the best selling album of the 20th century in the U.S. They are the fifth-highest-selling music act and the highest-selling American band in U.S. history.

The Eagles (Frey, Henley, Walsh, and Schmit) were slated to receive Kennedy Center Honors in 2015, but this was deferred to 2016 due to Frey's health problems.

On January 18, 2016, founding member Glenn Frey died at the Columbia University Medical Center in New York City at the age of 67. The causes of his death were rheumatoid arthritis, acute ulcerative colitis, and pneumonia while recovering from intestinal surgery.

In March 2017, it was announced that the band would be headlining the Classic West and Classic East concert events in July 2017, which were organized by their manager Irving Azoff. Glenn Frey's son Deacon performed in Glenn's place, along with country musician Vince Gill. At the Classic West concert on July 15, the band was joined by Bob Seger who sang "Heartache Tonight", which he co-wrote. Deacon Frey was noted for his composure and precision.

A North American tour, again with Frey and Gill, began in March 2018. Henley's son Will joined the touring band as a Guitarist.