Michael "Mikey" Klebitz is the older brother of Johnny Klebitz. He's currently a Captain in the United States Army or the United States Marine Corps serving in the Middle East.
He e-mails Johnny during the course of The Lost and Damned. Michael's e-mails suggest he is a law abiding citizen, criticizing Johnny for his criminal activities. Johnny responds, saying that he knows what he is fighting for. Michael and Billy Grey were friends at the age of thirteen, and he introduced Johnny (aged ten at the time) to Billy. Though criticizing him, they both seem to have a good relationship as brothers.