Jacques Joseph O'Mahoney (February 7, 1919 – December 14, 1989), known professionally as Jock Mahoney, was an American actor and stuntman.

Often cast alongside heroine Christine McIntyre, he appeared in the Stooge films Out West (1947), Squareheads of the Round Table (1948) (and its 1954 remake, Knutzy Knights), Fuelin' Around (1949), and Punchy Cowpunchers (1950).

Beginning in 1950, Columbia management noticed Mahoney's acting skills and gave him starring roles in two adventure serials, Cody of the Pony Express (1950) and Roar of the Iron Horse (1951).

Mahoney succeeded stuntman Ted Mapes as the double for Charles Starrett in Columbia's The Durango Kid Western series.

[3]: 22–25 The Durango Kid wore a mask covering much of his face, enabling Mahoney to replace Starrett in the action scenes.

Mahoney contributed so much to this series that he was awarded featured billing and major supporting roles as well, first as villains and then as sympathetic characters.

The first film was completed but never released; Columbia abandoned the series in June 1952,[5] bringing an end to its long history of B-Western production.

He had a Pawnee companion named Pahoo Katchewa ("Wolf Who Stands in Water"), played by actor X Brands.

Mahoney's strong presence, work ethic, and lean (6 foot, 4 inch, 220 pounds) frame impressed producer Sy Weintraub, who wanted a "new look" for the fabled apeman.

When this film was released, Mahoney, at 44, became the oldest actor to play the jungle king, surpassing Weissmuller and P. Dempsey Tabler, a record that still stands.

Owing to his health problems and the fact that producer Weintraub had decided to go for a "younger look" for the apeman, his contract was mutually dissolved.

Mahoney made three appearances on the Ron Ely Tarzan series--The Ultimate Weapon (1966), The Deadly Silence (1966) (a two-part episode, later edited into a feature film), and Mask of Rona (1967).

Mahoney was cast as an engineer, Andy Prentis, in the 1954 episode, "Husband Pro-Tem," on the syndicated anthology series, Death Valley Days, hosted by Stanley Andrews.

In February 1953, Mahoney co-starred with his wife Margaret Field in the Death Valley Days episode "Swamper Ike".