This band has rotated through a number of members since releasing their debut album A Fever You Can't Sweat Out in 2005. Original members included Ryan Ross, Spencer Smith, Brent Wilson, and Brendon Urie. Wilson was announced to have left the band in 2006, and was subsequently replaced with Jon Walker. After the release of their album Pretty. Odd. in 2008, Ross and Walker announced that they would also be leaving Panic! at the Disco, due to creative differences, with Ross citing his desire to create more of a retro sound as opposed to Urie's desire for the band to pursue pop music.
The two formed the musical group, The Young Veins, in 2009, though it was announced that they had gone on an indefinite hiatus after only a year. As a solo artist, Jon Walker has released two solo albums which you can listen to here on his Bandcamp. While Ross was credited as a writer on Vices & Virtues, Panic! at The Disco's first album released after his departure, those contributions were made prior to the band's breakup. In 2018, Ross mentioned that he would be in the studio, recording songs for a solo release.
After Ross and Walker's departure, Dallon Weekes joined the band, alternating between taking on a role as an official member of the band and a touring member before announcing his departure in 2017 to focus on his own band, I Don't Know How But They Found Me. As a duo, Smith and Urie released two albums, Vices & Virtues and Too Weird to Live, Too Rare to Die! before Smith announced that he was leaving the band due to addiction issues, and currently works as a talent agent for the music label DCD2 as of 2018.
Urie has released two albums under Panic! at the Disco as the main songwriter, and the band has since transitioned into a "solo project" as he is the sole original member of the band.