Green Day is a band.
American Idiot is the seventh studio album by American rock band Green Day . Green Day . For much of the group 's career , the band has been a trio with drummer Tré Cool , who replaced former drummer John Kiffmeyer in 1990 prior to the recording of the band 's second studio album , Kerplunk ( 1991 ) . Insomniac is the fourth studio album by American punk rock band Green Day , released on October 10 , 1995 by Reprise Records . Frank Edwin Wright III ( born December 9 , 1972 ) , known professionally as Tré Cool , is a German-born American musician , drummer and composer , best known as the drummer for the punk rock band Green Day .