Answer by taking a quote from the following article:

Frey was born in Detroit, Michigan. Growing up in Royal Oak, Michigan, he studied piano at age five, later switched to guitar, and became part of the mid-1960s Detroit rock scene. One of his earliest bands was called the Subterraneans, named after Jack Kerouac's novel, and included fellow Dondero High School classmates Doug Edwards (later replaced by Lenny Mintz) on drums, Doug Gunsch and Bill Barnes on guitar and Jeff Hodge on bass. Immediately after graduating from Dondero in 1966, he was invited to join The Four of Us, a local band led by Gary Burrows who had seen him performing with the Subterraneans.

Frey met drummer Don Henley in 1970. They were signed to the same label, Amos Records, at that time and both spent time at the Troubadour. When Linda Ronstadt needed a backup band for an upcoming tour, her manager John Boylan hired Frey because he needed someone who could play rhythm guitar and sing. Don Henley was approached by Frey to join Ronstadt. Randy Meisner and Bernie Leadon were also hired, although as the backing band personnel changed through the tour, the four had only played once together at a gig at Disneyland. Frey and Henley decided to form a band together while on the tour, and they were joined by Meisner on bass and Leadon on guitar, banjo, steel guitar, mandolin and dobro, forming the Eagles, with Frey playing guitar and keyboards and Henley playing drums. The band went on to become one of the world's best-selling groups of all time. Frey wrote or co-wrote (often with Henley) many of the group's songs, and sang the lead vocals on a number of Eagles hits including "Take It Easy", "Peaceful Easy Feeling", "Already Gone", "Tequila Sunrise", "Lyin' Eyes", "New Kid in Town", "Heartache Tonight" and "How Long".  The Eagles broke up around 1980 and reunited in 1994, when they released a new album titled Hell Freezes Over. The album had live tracks and four new songs. The Hell Freezes Over Tour followed. In 2012 on The Tavis Smiley Show, Frey told Smiley, "When the Eagles broke up, people used to ask me and Don, 'When are the Eagles getting back together?' We used to answer, 'When Hell freezes over.' We thought it was a pretty good joke. People have the misconception that we were fighting a lot. It is not true. We had a lot of fun. We had a lot more fun than I think people realize." At their first live concert of 1994, Frey told the crowd, "For the record, we never broke up. We just took a 14-year vacation."  The Eagles' album Long Road Out of Eden was released in 2007, and Frey participated in the Eagles' Long Road Out of Eden Tour (2008-2011).  In May 2012, Frey was awarded an honorary Doctorate of Music from Berklee College of Music along with Henley, Joe Walsh and Timothy B. Schmit.  In 2013, the two-part documentary History of the Eagles, directed by Alison Ellwood and co-produced by Academy Award winner Alex Gibney, was aired on Showtime. The documentary won an Emmy Award in 2013 for Outstanding Sound Mixing For Nonfiction Programming. An accompanying two-year History of the Eagles world tour ended on July 29, 2015 at Bossier City, Louisiana, a concert which would be Frey's final public appearance with the band.

who else joined?
Frey and Henley