After attending Stanford University, where he was a member of the Alpha Sigma Phi fraternity,[2] he trained as a theatre actor at the Pasadena Community Playhouse and subsequently performed on Broadway, continuing to return to the stage periodically throughout his career.

In the Victorian-era stage melodrama The Drunkard – played for laughs in a popular local revival – Kleinbach appeared as the wizened old villain "Squire Cribbs".

He appeared as the African tribal chieftain M'Tara in Tarzan and the She-Devil (1953), and a French army captain in Vera Cruz (1954).

In 1958, he portrayed Acacius Page in Auntie Mame and on television starred in the episode "The Tall Man" of the NBC anthology series Decision.

In 1960, he played a Native American character again as Running Wolf in the episode "Gold Seeker" in the television series The Rebel.

"Angel of Death" and "The Assassins", of the television series Adventures in Paradise and played an American Indian chieftain again in John Ford's Two Rode Together.