Most of Mahoney's films of the late 1940s and early 1950s were produced by Columbia Pictures. Like many Columbia contract players, Mahoney worked in the studio's two-reel comedies. Beginning in 1947, writer-director Edward Bernds cast Mahoney in slapstick comedies starring the Three Stooges. Mahoney had large speaking roles in these films, and often played his scenes for laughs. Often cast alongside heroine Christine McIntyre, Mahoney appeared in the Stooge films "Out West" (1947), "Squareheads of the Round Table" (1948) (and its remake, "Knutzy Knights" (1954)), "Fuelin' Around" (1949), and "Punchy Cowpunchers" (1950). In the Stooge films, Mahoney—striking a heroic pose—would suddenly get clumsy, tripping over something or taking sprawling pratfalls.