John O'Reilly began his career in the jazz genre, working as the drummer for Earth Fatha Jones. He also performed during the 1970s with JF Murphy and Soul Up. His next move was onto the band Whiplash, a rock group. He signed up as drummer for Rainbow in 1993, staying with that group until 1995 when he joined Blue Öyster Cult. He did not stay with that group for long, going back to Rainbow in 1996. He is the drummer for Westworld. He has also performed with Randy Coven and Brian Gottesman.
John O'Reilly is one of the Rainbow-connected drummers, who joined Blue Öyster Cult after Chuck Bürgi left in the fall of 1995.
John started off as a jazz drummer, playing with Earl Fatha Jones and JF Murphy & Soul Up in the mid-70s. He then moved on to rock and roll with a band called Whiplash. In 1980 he recorded demos with Yoko Ono for the Double Fantasy sessions. Later he played for Richie Havens, Peter Noone (Herman's Hermits), and CPR (Randy Coven-Al Pitrelli-John O'Reilly).
In 1993 he recorded with Joe Lynn Turner and then joined Ritchie Blackmore's Rainbow. He joined Blue Öyster Cult in September of 1995 and stayed on until August of 1996. He was replaced by Bobby Rondinelli.
After Blue Oyster Cult, John played and toured again with Richie Blackmore.
More currently John is working in the band Westworld with former TNT member Tony Harnell and Riot's Mark Reale.