Starting in the late 1970s, Koslo appeared (usually as a villain) in a string of television shows such as The Rockford Files, Mission: Impossible, The Incredible Hulk, Quincy, M.E., Buck Rogers in the 25th Century, T. J. Hooker, The A-Team, The Fall Guy, Dallas and Hunter. He also appeared as Jesse James in The Dukes of Hazzard seventh-season episode "Go West, Young Dukes". More recently, along with television appearances, he has been in several independent action films (most of them straight-to-video). He was also in Loose Cannons (1990) with Gene Hackman and Dan Aykroyd and appeared as the Russian battle-robot pilot Alexander in the cult science fiction film Robot Jox (1990).
Koslo met his wife, Allaire Paterson Koslo, at the MET Theatre in Hollywood, when he produced a one-woman show, Purple Breasts, a critically acclaimed play she co-wrote and starred in. They married in 1997 and have one child together.
