The 1940 United States Census shows Jack Mullaney living on Minot Avenue in the Oakley neighborhood of Cincinnati, Ohio.

[2] He also portrayed United States Navy Lieutenant (junior grade) Rex St. John in NBC's Ensign O'Toole (1962–1963).

[3]: 516 In the 1958 film South Pacific, based on the Rodgers and Hammerstein hit musical, he played a character affectionately known as the "Professor."

He appeared as murderer Bert Rockwood on episode #227 of Lee Marvin's M Squad, titled "The Vanishing Lady," which first aired April 3, 1959, and also had a small, but important, role in the 1964 political thriller Seven Days in May.

He worked in two Elvis Presley features late in the rock singers film career, 1965's Tickle Me and Spinout in 1966.