At 51 years old, Mike Dirnt has this physical status:
While at Pinole Valley High School, Dirnt and classmate Armstrong formed a band called Sweet Children. Dirnt's mother struggled to provide for him and his sister as a single parent and eventually had to leave Rodeo in 1987 to look for work. Unwilling to leave Sweet Children, Armstrong and Dirnt convinced each other's parents to allow Dirnt to move into Armstrong's garage. After drummer John Kiffmeyer, who was also known as Al Sobrante, joined the group and replaced original drummer Raj Punjabi, Sweet Children began performing at 924 Gilman Street. The band performed several well-received sets, which encouraged Armstrong to drop out of high school to focus his energy on music. Dirnt, however, worried that he needed a backup plan and continued his studies. Bass player Sean Hughes, who was not as dedicated to the group as the other members, left Sweet Children, leaving Dirnt to play bass. Dirnt often brought his bass to school, and the plucking noise of the unamplified strings led classmates to jokingly call him by the onomatopoeia "Dirnt". After changing its name to Green Day, the band recorded its debut album 39/Smooth over the 1989 Christmas holiday break and went on its first van tour in June 1990, leaving the day that Dirnt graduated from high school.
At Woodstock '94, Green Day started an infamous mud fight, during which several fans invaded the stage. Overwhelmed by the chaotic situation, concert security mistook the mud-soaked Dirnt for a fan and tackled him, knocking out one of his teeth. Dirnt required emergency orthodontia due to this incident.
While performing at the 1998 KROQ Weenie Roast in Irvine, California, Third Eye Blind bassist Arion Salazar ran onstage and "bear-hugged" Dirnt, who was caught off-guard. The incident escalated into an on-stage scuffle before security escorted Salazar away. After the performance, Dirnt confronted Salazar backstage, and as the two argued, a beer bottle struck Dirnt in the head, causing a small fracture in his skull. Eyewitnesses later attributed the bottle-throwing to a fan of Third Eye Blind, though this was disputed by another eyewitness on the following day's Loveline broadcast. Salazar and the band's management soon released a statement: "I am sorry that my attempt at doing something I thought would be funny escalated into Mike getting hurt. That was never my intention. I simply had too much to drink and made a very bad decision. If I had been in Mike's place, I am sure I would have acted similarly. My heart goes out to him and I hope he recovers quickly."
Dirnt helped form the secret Green Day side project The Network during the summer of 2003. The six-piece new wave band consists of the members of Green Day, along with touring members and friends of the band. They released their debut album Money Money 2020 on September 30, 2003. After a seventeen-year hiatus, the band released their second album, Money Money 2020 Part II: We Told Ya So!, on December 4, 2020. In addition to playing bass for the band, Dirnt also provides lead vocals on many of their tracks (in contrast to his work with Green Day, where he primarily provides backing vocals).
In the live album, Bullet in a Bible, Armstrong calls Dirnt "the best bass player in the history of punk rock".
In 2007, during the recording of Green Day's eighth studio album 21st Century Breakdown, Dirnt, Armstrong, and drummer Tré Cool formed the garage rock side project, Foxboro Hot Tubs. In addition to the three members of Green Day, the band also includes Green Day touring members Jason White, Jason Freese and Kevin Preston. They released their debut album Stop Drop and Roll!!! in 2008. Dirnt played bass and provided backup vocals on the album.
In 2012, during the iHeartRadio Music Festival, Dirnt and Armstrong smashed their respective bass and guitar after Armstrong became agitated onstage and ranted about Green Day's set being cut short for Usher.
On April 18, 2015, Dirnt and his Green Day bandmates were inducted into the Rock and Roll Hall of Fame in their first year of eligibility.