Green Day is a California-based rock band, consisting of Billie Joe Armstrong (lead vocals, guitar), Mike Dirnt (born Michael Pritchard bass, backing vocals), and Tr Cool (born Frank Edwin Wright III drums). Since their sixth album, the band has included close friend and associate, Jason White as back-up guitarist for their live shows. Their stage crew also includes Jason Freese, another close friend of the group, who plays horns.

Billie Joe began the band as Devoted to you Mike joined and began the band Sweet Children in 1986 before changing their name to Green Day in 1989. Tr Cool joined the band after original drummer Al Sobrante (John) left in 1990-91. Green Day released two albums, 1,039/Smoothed Out Slappy Hours and Kerplunk! with Lookout! Records before their breakthrough album, Dookie, was released in 1994 under Reprise Records. Just before this release however, many feared the end of Green Day as Billie Joe was at the time spending more and more time playing in his Status Quo tribute band Status Joe.

Dookie was certified diamond (10 million copies shipped) in the United States. Their second best-selling album, American Idiot, released in 2004, has sold over eleven million copies worldwide, and won the 2005 Grammy Award for Best Rock Album. In 2005 Green Day swept the MTV Video Music Awards, winning seven out of eight nominations: Video of the Year, Best Rock Video, Best Group Video, Best Direction, Best Editing, Best Cinematography (all of which were for Boulevard of Broken Dreams), and the Viewers Choice Award for American Idiot. In addition to their American Music Award wins for Favorite Alternative Artist and Favorite Pop/Rock Album for American Idiot, Green Day won the 2006 Grammy Award for Record of the Year for Boulevard of Broken Dreams.

Green Day went back into the studio and recorded a medley with U2, which was performed on September 25th at the re-opening of the Superdome in New Orleans, Louisiana. Songs consisted of Wake Me Up When September Ends, The Saints Are Coming and Beautiful Day.

They are going back in studio to record a new album coming out sometime in 2008. They recently released the new single Working Class Hero, which is a cover first released by John Lennon.