It all started when Mike and Billie Joe became friends and formed  a band called Sweet Children.
Their first gig was when they were only 15, and a success of 30 friends showed up. Two years
later both friends went on tour only with different bands. Billie Joe played guitar for the Corrupted Morals, while Mike sang for the Crummy Musicians. Then after proving themselves  a great band, Billie Joe, Mike and drummer John Kieffmyer got a record deal with Lookout! Records. In 1990, they released 39/smooth and their E.P.'s Sweet Children, 1,000 hours, and Slappy. Then they changed there name to Green Day. The day after Mike's graduation was when Green Day's first tour started. So in 1991 they put all the E.P.'s together to form the album 1039/Smoothed Out Slappy Hours. Then John left the band to go to collage and was never heard from again. It didn't take the band long to find there next drummer Tre Cool.
After that the second album, kerplunk! which gave them minor fame. Then in 1993, they had chosen a decision that was to make them un-welcome in the whole Gillman punk scene, theyswitched from independent label to Reprise Records (a major label). After that, there was no turning back. Their producer Rob Cavallo produced one of the most well known multi-platnum record Green Day has so far ever made in released in February of 1994, Dookie. They ended up in Woodstock 1994, that's when mike lost his two front teeth. And did Lollapalooza also. Then in October 1995, they released there forth album, Insomnaic. Insomniac only sold six million copies, unlike Dookie which sold 11 million. In 1996, they cut short their European tour, and Green Day practically disconnected themselves from the music industry, but planing their fifth album, released in October of 1997, called Nimrod. Then after about another year and a half of touring they stopped and concentrated on their personal lives. Years would pass with no new album, but during this time they would practice a song a week in Billie Joe's house.
The summer of 2000, they went on the Warped Tour, for the first time. Until, finally, in October of 2000, they released "Warning", and then did a summer tour.