Ed McMahon had a strange job while he was alive. His job was to laugh at Johnny Carson. Plenty of people already did that for free. From 1962 to 1992 his job was to sit on stage and laugh like a monkey. It's no where near where he began his career. He began as a carnival barker in Mexico, Maine about 50 miles from Augusta. He put himself through college as a pitchman for vegetable slicers on the Atlantic City boardwalk. Somewhere in the middle of all that, he did some work in radio.
His first broadcasting job was at 1400 WLLH-AM in his native Lowell, Massachusetts. He studied electrical engineering at Boston College and it enabled him to do his remotes solo, a plus for hiring managers. McMahon's voice was heard on WLLH doing station IDs in the 1980s, and he returned to Lowell in 1994 to be honored with a live broadcast on WLLH alongside then-morning host Paul Sullivan. WLLH-AM was a whopping 250 watt station back in those days. Today it's an ESPN affiliate with a more substantial 1000 watts. More here.
In 1949 Ed scored a gig doing overnights at WCAU-AM in Philadelphia where he was the announcer for The Ol' Night Owl, Powers Gouraud . He also co-hosted an afternoon program. He also did some announcing on WCAU-TV. Nobody is proud of it now, but he also was a clown on Saturday Mornings. He was drafted twice. Once in WWI and once in the Korean war both tours flattening his broadcasting career. This second tour was when he was at the peak of his work in Philadelphia. By 1952 he had bits on 13 different programs; new game shows, and the late night movie program. He had learned to fly in WWII so now they wanted him to bomb small islands in the pacific. When he got back they were all cancelled. He got a little piece on the nightly news. Philly was over he started looking at New York. But in 1958 he was still in Philadelphia, still on WCAU. but Agent Chuck reeves set him up with an audition for announcer on Johnny Carson's show on ABC. It was called "Who Do you trust." It was in actuality a game show but most of it was Carson being a funny man in the classical sense. That show ran for four years. In 1962 the two of them started on the tonight show replacing the twitchy Jack Paar on NBC.
For Ed that was really the end of radio. He came back to WLLH a couple times to do some station IDs as a favor to be friendly to the station that started him at $10 a week. He came back again when they celebrated Ed Mcmahon day with a parade. In the 1990s, on the USA Radio Network he hosted a weekend talk program called "Lifestyles Live." I think that was his last spin in radio. He died June 23, 2009. He was at 86.