DeBenning appeared in nearly 100 films and TV shows including the television films The House on Greenapple Road (1970), Brinks: The Great Robbery (1976) and Hanging by a Thread (1979). He appeared in such television programs as Custer, Nakia, Matlock, Matt Houston, Mike Hammer, Magnum, P.I., The Virginian, Rockford Files, Matt Helm, Medical Center, McCloud, Ironside, Columbo and Medical Story. He also co-starred with Robert Wagner in City Beneath the Sea (1971). His character was called "Aquila" and had gills. His film appearances included Beach Red (1967), Sweet November (1968), St. Ives (1976), The Incredible Melting Man (1977), Armed Response (1986), A Nightmare on Elm Street 5: The Dream Child (1989), and Love Field (1992). In 1977 he guest starred in the second pilot film titled The Death Scouts for the TV series called Man from Atlantis. He played Lt. Jim Porter, a Navy Intelligence agent, in the 1978 science fiction TV miniseries, The Return of Captain Nemo, originally shown on U.S. TV as a three part miniseries (50-minutes each episode) and later released theatrically outside the U.S. in a 102-minute widescreen version renamed The Amazing Captain Nemo.