Ed McMahon, 86, who began his half-century television career in Philadelphia before becoming Johnny Carson's sidekick on The Tonight Show where his stentorian booming announcement "Heeere's Johnny!" became his trademark, died this morning.

Publicist Howard Bragman told the Associated Press that McMahon died at Ronald Reagan UCLA Medical Center surrounded by his family.

Bragman didn't give a cause of death, saying only that McMahon had a "multitude of health problems the last few months."

"One of the best times in my career was to substitute host 75 times for Johnny Carson and have Ed McMahon on my right hand side," said comedian David Brenner. "God now has the best side kick with Him."

"The Tonight Show was powerful. It launched the careers of many comedians," said stand-up comic Tom Dreesen, of Los Angeles, who appeared on the show 61 times. "Johnny Carson didn't speak with guests before the show. Ed McMahon would."

"The show had about 15 million viewers and the first time I performed I was obviously nervous. Ed McMahon put his arm around my shoulder and said, 'Have fun and the audience will have fun.' I never forgot that. I think about that every night before I go on stage to this day. Nobody had more fun than Ed McMahon. He had a hearty, distinctive laugh."

Best known as Johnny Carson's laugh track, Mr. McMahon got his start in television in Philadelphia in 1949 and he remained on local shows here until 1958, with his career interrupted for several years while he served as a flight instructor in Korea during the war.

Mr. McMahon's first television job was at Channel 10 WCAU shortly after graduating from Catholic University. His first day on the job, Mr. McMahon was writer, producer and co-host of a live three-hour daily show. There were so few television sets at the time it didn't matter much if he made mistakes on the air.

"Ed sometimes filled in for me as emcee on Fame and Fortune talent show, which included doing the commercials for Erlanger Beer," said longtime WCAU weatherman Gene Crane. "The sponsor made him do the commercial over and over, each time drinking a beer. He was a little bombed when he returned to the show, but was a pro. Ed was fun and worked harder than any of us."

Over the next nine years, Mr. McMahon became a familiar face on 13 different local shows, mostly for Channel 10. He was a clown on Big Top, the nephew on the cooking show Aunt Molly's Den, the host of Cold Cash and Million Dollar Movie and featured visiting celebrities on the first morning show, Strictly for Girls. He also hosted McMahon and Company for Channel 3 (then WRCV-TV).

"Ed wore a fake bald head wig over his hair as a clown on Big Top," said John Zacherle, host of WCAU's late-night horror movie. "He started the show by looking into the camera, bowing his head, and 'BIG TOP' was written on his bald spot."

Mr. McMahon's last show at WCAU, Five Minutes More, was a commentary at the end of the 11 p.m. news. "I was the producer and was only 21," said Jim Hirschfeld, who went on to produce Captain Kangaroo. "Ed and I met everyday for lunch at Cynwyd Lounge on City Avenue and wrote the show over two martinis and a hamburger."

He also had home in Avalon and when the Tonight Show was in New York, Carson, who died in 2005, would ask Mr. McMahon about his getaways to the Shore.

Even though his schedule was jam packed in Philadelphia, Mr. McMahon had set his sights on New York and network television. He took the train to New York, set up his office in a Manhattan phone booth with a pocketful of nickels and called producers for a gig. He got a short-lived start as host of Bride and Groom for NBC, in which couples were married on the air. The show was canceled after six weeks and McMahon acknowledged in later years "it was a terrible show."

Mr. McMahon's big break came when Edward R. Murrow met him while in Philadelphia to interview Dick Clark, teen idol of American Bandstand.

Clark and Mr. McMahon were neighbors in Drexelbrook apartments in Drexel Hill in the 1950s.

"Fifty years ago, Ed and I were next-door neighbors in Philadelphia," Dick Clark said from Los Angeles.. "Over the years, our friendship grew while he became one of America's favorite television personalities. We were together for years. Ed was a big man, had big talent and a really big heart. We'll all miss him."

Mr. McMahon emceed an impromptu show at a party Murrow threw for Clark. Among the guests was Chuck Reeves, Clark's producer, whose New York office was in the same building as the young comedian Johnny Carson.

Reeves passed Mr. McMahon's name to Carson in 1958 when he was looking for an announcer for his new game show Who Do You Trust? Mr. McMahon won Carson over from their first show.

"Johnny made it a comical situation from the very first day when he set fire to the script. I had read off all the sponsors, but I didn't know all the little refrains. I tried to read as my script turned to charcoal before my eyes. From that moment on, I became his foil . . . whatever he wanted me to be," Mr. McMahon said in a 1984 Inquirer interview.

In 1962, Carson replaced Jack Paar on NBC's The Tonight Show and Mr. McMahon came along. The two appeared together weeknights for the next three decades.

Edward Leo Peter McMahon Jr. was born in Detroit on March 6, 1923. Mr. McMahon's father was a professional fund-raiser and salesman whose finances soared and plunged. The family moved 40 times by the time he was 4. "I was in more towns than a pickpocket," Mr. McMahon said in 1984.

In 1936, the family lived in Olney for a year. Mr. McMahon went to Olney High School his sophomore year but did not make many friends, he said. By then he had attended 14 different schools. When his parents moved again, he demanded to live with his grandmother in Lowell, Mass., until he graduated from high school in 1939.

In his grandmother's parlor he practiced being an announcer and disc jockey. He played records ("Let's Dance" by Benny Goodman was his theme song) and did commercials, using a flashlight as his microphone, pitching directly from a magazine.

As a teen, Mr. McMahon hawked vegetable slicers on the Atlantic City Boardwalk and was an announcer at carnivals and bingo games He added suspense by elongating the numbers, "Unnnderrr the O. . .. its SIXXTEEE ... seven."

"That's probably where 'Heeeere's Johnny' came from," he said.

Mr. McMahon was trained as a Marine fighter pilot during World War II. When the Korean War broke out he was activated as a flight instructor in Korea until 1953. He was discharged in 1966 as a colonel from the Marine Reserve.

After World War II, Mr. McMahon married his college sweetheart, Alyce Ferrille. He earned a bachelor's in speech and drama in 1949 from Catholic University in Washington. The couple had four children before the marriage ended in divorce in 1976.

That same year, he married former stewardess Victoria Valentine, 23 years his junior, and they adopted a daughter. The marriage ended in divorce in 1989.

Mr. McMahon, who required only four hours of sleep a night, always added more work to his schedule. In 1983, he became host of the syndicated talent show Star Search. He co-hosted TV's Bloopers & Practical Jokes with Clark and often appeared on Jerry Lewis' Muscular Dystrophy Association telethons.

Millions of viewers knew Mr. McMahon as a commercial pitchman: "You may have already won 10 million dollars!," for the American Family Publishers' sweepstakes; "Budweiser, the only beer that's beechwood aged;" and "You can't be turned down," for life insurance.

In 2001, Mr. McMahon was awarded a $7.2 million insurance settlement after he and his wife were sickened by toxic mold in their home, but after he broke his neck in 2007 he stopped television work and fell on hard times. Mr. McMahon and his wife were threatened with foreclosure on their Beverly Hills home in 2008 until his mortgage was anonymously bought out.

His last television commercial was when Mr. McMahon lampooned his financial woes in a Cash 4 Gold ad on Super Bowl Sunday this year. He dolefully sold his gold cufflinks, gold microphone, gold golf clubs, gold hip replacement and gold toilet.

In addition to his wife, Pamela, Mr. McMahon is survived by daughters Linda Schmerge, Katherine James and Claudia McMahon; sons, Jeffrey and Alexis; and eight grandchildren. His son, Michael, died of cancer in 1995.