John Dolmayan was born in Beirut, Lebanon.
John Dolmayan first became interested in drums at the age of two. His father was a saxophone player and when his mother would take him to watch his father play, he would mimic his father's drummer. He learned to play the drums by putting on records and practicing, "4-6 hours a day, depending on the particular day.
Dolmayan is a fan of The Who and cites Who drummer Keith Moon as his biggest influence. Other drummers that he cites as major influences include Led Zeppelin's John Bonham, Stewart Copeland from The Police, and Rush's Neil Peart.
John Dolmayan joined System of a Down in 1997 after their original drummer, Ontronik "Andy" Khachaturian, left the band after a hand injury. Dolmayan recorded five albums with System of a Down: System of a Down (1998), Toxicity (2001), Steal This Album! (2002), and, most recently, Mezmerize (2005), and Hypnotize (2005).
After System of a Down went on hiatus in 2006 Dolmayan teamed up with Daron Malakian (System of a Down's guitarist/vocalist) to form a new band called Scars on Broadway, which recorded their eponymous debut album in 2007 and 2008. The album was released in the summer of 2008 and Dolmayan, Malakian, guitarist Franky Perez, bassist Dominic Cifarelli, and keyboardist Danny Shamoun performed concerts and prepared to embark on a tour in support of the album before Malakian suddenly cancelled the tour in October 2008.
In August 2009, Dolmayan, Franky Perez, Danny Shamoun, and Dominic Cifarelli as Scars on Broadway traveled to Iraq for a USO tour across the U.S. army bases. Their setlist consisted of covers as well as a few Scars on Broadway songs. Scars on Broadway reunited with Malakian on May 2, 2010.
Dolmayan recorded drums for Killing Joke's 2003 self-titled album.
He also played drums on the Axis of Justice concert tour with various artists, on the Serj Tankian solo debut, Elect the Dead and joined Tool on stage for a few shows.
In June 2009, Dolmayan began forming a new rock band called Indicator with three friends from Southern California who were formerly in a punk rock band, Tom Capossela, Ryan Huber, and Ryan Murphy. The band played their first show at The Bitter End on July 22, 2009, with Dolmayan's fellow Scars on Broadway member Franky Perez joining the band for a few songs. The band plans on releasing an album called, Have We Gone Too Far?
Dolmayan performed with System of a Down bandmates Malakian and bassist Shavo Odadjian and Scars on Broadway guitarist Franky Perez for Odadjian's Holloween show. Dolmayan, Malakian, and Odadjian performed together again in November 2009 during a charity show for Deftones bassist Chi Cheng.