Beginning in 1950, Columbia management noticed Mahoney's acting skills and gave him starring roles in adventure serials. He succeeded stuntman Ted Mapes as the double for Charles Starrett in Columbia's "Durango Kid" Western series. The Durango Kid often wore a mask covering much of his face, which enabled Mahoney to replace Starrett in the action scenes. Mahoney's daring stunts made it seem that the older Starrett grew, the more athletic he became. 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. By 1952 Columbia was billing him as Jack Mahoney.