In what year was Green Day formed?

Green Day was formed in 1987 in Rodeo, California. The original teenage lineup centered on guitarist and singer Billie Joe Armstrong and bassist Mike Dirnt, who were both 15 years old at the time.

The group initially used the name Sweet Children and played early shows in the East Bay punk scene. Their first live performance took place on October 17, 1987, at Rod’s Hickory Pit in Vallejo, California. Drummer John Kiffmeyer, known as Al Sobrante, later became an important member of the early lineup.

In 1989, shortly before releasing their debut EP “1,000 Hours,” the band changed its name to Green Day. The expression referred to spending a day smoking marijuana, and it was familiar slang in the Bay Area punk community. The band’s first studio album, “39/Smooth,” followed in 1990 on Lookout! Records.

Green Day’s worldwide breakthrough came later with “Dookie,” released in 1994 through Reprise Records. The album helped bring California punk and pop-punk to a huge mainstream audience, but the band’s formation dates to its small-club beginnings in 1987.