Koslo started his career in such 1970s films as ''
Nam's Angels a.k.a. The Losers
, Vanishing Point and The Stone Killer. He also appeared opposite Charlton Heston in the science fiction film The Omega Man, in a sympathetic co-starring role. He portrayed villains in Joe Kidd (1972), Mr. Majestyk (1974), and The Drowning Pool'' (1975). He and fellow
Omega Man co-star
Anthony Zerbe also appeared in
Rooster Cogburn (1975). After a solid supporting part as a Jewish
concentration camp survivor in the critically acclaimed
Voyage of the Damned (1976), as well as the mayor in ''
Heaven's Gate (1980), he began a long run of portraying villainous types in productions such as Roots: The Next Generations and The Glitter Dome. In rare, in-depth interviews with both Psychotronic Video and Shock Cinema
(issue No. 14) magazines, Koslo spoke about his experiences working in several films with Charles Bronson and in The Omega Man'' with Heston. Starting in the late 1970s, Koslo appeared (usually as a villain) in a string of television shows such as
The Rockford Files,
Mission: Impossible, Barnaby Jones,
The Incredible Hulk,
Quincy, M.E.,
Buck Rogers in the 25th Century,
T. J. Hooker,
The A-Team,
The Fall Guy,
Dallas and
Hunter. In the
Highway to Heaven episode "The Torch" he played a leader of the
American Nazi Party. Koslo found it tough to deliver his character's often bigotry-riddled dialogue, and during the filming of a scene set at a Nazi rally the cast and crew were heckled by passers-by, since the scene was
filmed on location in
downtown Los Angeles with
swastikas decorating the outside of a building. He also appeared as
Jesse James in
The Dukes of Hazzard seventh-season episode "Go West, Young Dukes". In the 1980s, along with television appearances, he appeared in several independent action films (most of them
straight-to-video). He was also in
Loose Cannons (1990) and appeared as the Russian battle-robot pilot Alexander in the science fiction film
Robot Jox (1990). ==Personal life==