A former roommate of Keith Richards, his earliest work was in Broadway theatre, but while visiting Italy, he was cast in his first Western, Break Up, in 1965.

He also starred in the horror films Five Dolls for an August Moon, My Dear Killer, Monster Shark, and The Murder Clinic.

[1] In the early 1970s, Berger spent some time in an Italian prison, having been wrongly accused of possession of hashish and cocaine, but resumed his acting career after his release.

Berger collaborated with his good friend, famed Spanish horror film director Jesus Franco, appearing in seven of his films: The Sinister Eyes of Dr. Orloff, Night of the Killers, Faceless, Golden Temple Amazons, Love Letters of a Portuguese Nun,[2] Dirty Game in Casablanca,[3] and A Captain of 15 Years.

Berger starred with his son Kasimir in the TV miniseries Christopher Columbus and Tuareg – The Desert Warrior.