CNN reported the news of the celebrity's death early Tuesday at the Ronald Reagan/UCLA Medical Center in California, but did not immediately say what the cause was. McMahon had been hospitalized since last month for cancer, NBC said.
McMahon was to Johnny Carson what Hugh Downs had been to Jack Paar. And when Paar retired from the "Tonight" show, Carson stepped in as his successor and brought with him McMahon, who had been his foil on "Who Do You Trust?", as his "Tonight" associate from 1962 to 1992.
Edward Lee McMahon was born in Detroit on March 6, 1923. His family moved to Philadelphia and he worked his way through Catholic University, earning money through side jobs in Atlantic City. After receiving his bachelor's degree in speech, McMahon starred in a television show for children in Philadelphia.
During the Korean War, McMahon flew as a fighter pilot in the U.S. Marines.
Following his discharge from the Marines, McMahon teamed up with Carson on "Who Do You Trust?" He also landed roles in "The Incident" and the "Dick and Jane" movies, was a popular TV ad pitchman and served as co-host, along with Dick Clark, of the 1980s show "TV's Bloopers and Practical Jokes."
McMahon is survived by his third wife, Pamela, and five children. CNN said the star's son Michael died in 1995.