Glenn Frey, a founding member of the band the Eagles, has died. He died at 67 of complications from rheumatoid arthritis, which included pneumonia. (Jhaan Elker,Thomas Johnson/The Washington Post)

It was 1971, and Jackson Browne was working on a new song that he just couldn’t finish. Frustrated, he told his buddy, Glenn Frey, to give it a try. And with a single phrase — “it’s a girl, my Lord, in a flatbed Ford” — Frey invented the California country-rock sound and launched one of the biggest bands of all time.

“Take It Easy,” recorded by the Eagles and released in 1972, rose to No. 12 on the pop charts and introduced the world to the Detroit-born singer with the bloodshot eyes and outlaw moustache. The song also marked the beginning of the sometimes glorious, sometimes dysfunctional reign for the Eagles, a band that would go on to sell more than 150 million records.

Frey, 67, died Monday of what the band said were complications from rheumatoid arthritis, acute ulcerative colitis and pneumonia. His death came less than six months after Frey and the Eagles, which he co-founded with singer Don Henley, guitarist Bernie Leadon and bassist Randy Meisner, wrapped up their latest tour. Frey’s indulgences in the 1970s — drugs and women, mainly — were well known. But he just as famously became a health nut after the band’s initial breakup in 1980. The intestinal issues that emerged in the 1980s and that continued to dog him in recent years were, he has said, due at least in part to the damage done to his body during the band’s heyday.

In 1986, he missed a reunion with longtime bandmate Henley — the band had broken up for the first time in 1980 — at a benefit concert in California because of an intestinal disorder. An attempt to re-form the Eagles in 1990 was put off, in part, because of surgery to remove a large part of Frey’s intestine. And in 1994, the band’s “Hell Freezes Over” reunion tour was interrupted by Frey’s bout with diverticulitis. The tour resumed the following year.

Last year, Kennedy Center officials decided to postpone the Kennedy Center Honors award to the band because Frey needed surgery. A Kennedy Center spokesman said Monday that she had no word on any impact Frey’s death will have on next year’s Honors.

As the news broke, tributes rolled over social media from performers as diverse as Steve Martin, Questlove, Miles Teller and Nikki Sixx.

Henley, in a statement, described Frey as a brother and credited him with being “the one who started it all.”

“He was the spark plug, the man with the plan,” said Henley. “He had an encyclopedic knowledge of popular music and a work ethic that wouldn’t quit. He was funny, bullheaded, mercurial, generous, deeply talented and driven. He loved his wife and kids more than anything. We are all in a state of shock, disbelief and profound sorrow.”

In addition to “Take It Easy,” Frey sang lead on “Peaceful Easy Feeling,” “Already Gone,” “Tequila Sunrise,” “Lyin’ Eyes,” “New Kid in Town” and “How Long.” Though he began to write less as Henley asserted himself more — Frey sang lead on just one song on the band’s 1976 landmark album, “Hotel California” — he still played a central role in the group. He was also at the center of its combustible dynamics. Bernie Leadon, before leaving the band, famously poured a beer over Frey’s head. And in 1980, a dispute between guitarist Don Felder and Frey carried over onto the stage.

The exchange was captured deliciously on tape and shared on the band’s fascinating 2013 documentary, “History of the Eagles, Part One.” At one point, Frey, on stage, is heard taunting Felder with “I’m gonna [expletive] kill you. . . . I can’t wait.”

The “History” film detailed the band’s many incarnations. Leadon and Meiser left in the 1970s, replaced by bassist Timothy B. Schmit and guitarists Don Felder and Joe Walsh. Felder’s exit, in 2001, came after arguments with Frey and Henley over money and the guitarist’s frustration over not getting more creative input.

In the 1980s, a new Frey emerged. Drug-free, clean-cut and a gym freak. He even did a health-club commercial. He had solo hits with “The Heat Is On,” “You Belong to the City” and “Smuggler’s Blues,” and acted in “Miami Vice” and “Wiseguy.” He also played a National Football League general manager in Cameron Crowe’s 1996 smash, “Jerry Maguire.”

But ultimately, as his solo and movie career slowed, he returned to his signature band. The Eagles reunited in 1994, released a new studio album in 2007 and toured regularly. They wrapped up their “History of the Eagles” tour July 29.

Monday night, David Lindley,the multi-instrumentalist who was a central player in the early ’70s Los Angeles scene that included such figures as Browne, Warren Zevon and Linda Ronstadt, remembered hearing the Eagles version of “Take It Easy” for the first time.

Upon its release, Rolling Stone Magazine called it “the best-sounding rock single to come out so far this year.”

Lindley said he hoped Frey would be remembered as a musician who could hold his own with all of those key songwriters.

“They were all black belts,” Lindley said. “All of them. Especially when you contribute the two lines that really made the song. Those were important.”