He served in the United States Army Air Forces during World War II, earning a Purple Heart during his service.

In 1961, he played the mobster Legs Diamond in an episode of NBC's 1920s crime drama The Lawless Years with James Gregory.

[citation needed] Among his television appearances, Ellenstein guest starred in three episodes of Perry Mason.

In 1965 he played a character curiously of 65 years of age (in obviously inadequate makeup) in a second-season episode of The Man From U.N.C.L.E.

He directed many theatre productions in New York, Los Angeles and in regional theater.