Green Day started in 1987 as a teenage punk band in the East Bay, California, originally under the name Sweet Children before becoming Green Day a few years later.

Quick Scoop: How Green Day Started

  • Billie Joe Armstrong and Mike Dirnt formed their first band together in 1987 when they were around 14–15 years old.
  • The band was initially called Sweet Children and played small local shows around Rodeo and the wider East Bay punk scene.
  • As they developed a more defined identity and lineup, they changed the band’s name to Green Day and became part of the late‑80s Bay Area DIY punk circuit.
  • By the early 1990s they were deeply associated with the legendary 924 Gilman Street venue and the Lookout! Records scene, which helped launch them beyond the local underground.

In short: when people ask “when did Green Day start,” they’re talking about that 1987 moment when Billie Joe and Mike kicked off their first incarnation of the band that would soon become Green Day.

TL;DR: Green Day’s origins go back to 1987 in the East Bay, when Billie Joe Armstrong and Mike Dirnt formed Sweet Children , the band that evolved into Green Day.

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