Mike Portnoy was in Dream Theater.
Michael Stephen `` Mike '' Portnoy ( born April 20 , 1967 ) is an American drummer primarily known as the former drummer , backing vocalist , and a co-founder of the progressive metal/rock band Dream Theater . He co-produced six Dream Theater albums with guitarist John Petrucci , starting from Metropolis Pt . He is a founding member of Liquid Tension Experiment , an instrumental progressive rock band featuring fellow Dream Theater members John Petrucci and Jordan Rudess along with bassist Tony Levin .