He wasn't the first second banana, but he was surely the best of the bunch.

Hugh Downs did it earlier, if less memorably, for Jack Paar, but once "The Tonight Show" entered its glory years under Johnny Carson, Ed McMahon comfortably perfected the role of consummate sidekick, launching plenty of imitators who can still be seen laughing at the boss's jokes on late night television.

Mr. McMahon, who died yesterday in Los Angeles at age 86 of bone cancer, ably served as Sancho Panza to Mr. Carson's Don Quixote -- but not, it should be said, Ed Norton to his Ralph Kramden. Rather than provide comic relief, Mr. McMahon was the steady, brotherly affirmation of Mr. Carson's genius -- "Hey-O!" -- as well as safety net and reliable guffaw when the boss's jokes fell flat.

No boy or girl ever grew up wanting to be Ed McMahon, any more than they grew up wanting to be vice president of the United States, "and if they did their parents would probably wonder, where did I go wrong?" noted Robert Thompson, director of the Center for Television and American Pop Culture at Syracuse University.

"Usually human nature wants you to be first rather than second banana, but Ed was really good at what he did. He identified what the job was, and that was to be the mirror that reflected the glory of the star of the show."

Mr. McMahon worshiped Mr. Carson, comparing him, in his memoirs, to Joe DiMaggio and Leonard Bernstein. And if Mr. Carson was the perfect late night talk show host for the times, our father's or grandfather's comedian, the tightly wound guy with the golf swing who fiddled with the cuffs of his Botany 500 suits and made alimony jokes, Mr. McMahon, a big bear of a man with the puffy sideburns, was his perfect foil.

Indeed, he couldn't be more different from Hank Kingsley on the hit HBO show "The Larry Sanders Show," a TV character who, Mr. Thompson said, "was an example of what would have happened if Ed McMahon was not as good as he was. He always put his ego below the needs of the show, whereas Hank Kingsley always secretly resented the fact he was not the star. I have watched hundreds and hundreds of Johnny Carson 'Tonight Show' reruns, and I cannot remember a single Hank Kingsley moment."

Born in Lowell, Mass., Mr. McMahon learned his trade from his father, who eschewed the family business -- plumbing -- to tour carnivals and circuses with his son in tow, who in turn honed his own style by bingo calling and hawking kitchen slicers on Atlantic City's boardwalk.

Mr. McMahon's biography doesn't mention college, but Toni Uricchio, of Fox Chapel, remembers sitting between Mr. McMahon and her future husband, William Uricchio, in an Economics 101 class at Catholic University in Washington, D.C., in the late 1940s.

"He was so handsome, just a really nice, pleasant guy," Mrs. Uricchio recalled. "When I saw him on television later I thought, this is perfect. He was not seeking the limelight, but let Johnny Carson shine. He wasn't a clown, but a bit on the shy side."

Mr. McMahon later broke into television, in Philadelphia, hosting morning shows, game shows, late-night movies, even a women's issues show -- "Strictly for the Girls" -- before heading off to Korea. After struggling in New York, he got his big break when Mr. Carson selected him to be the announcer on his game show, "Who Do You Trust?"

Then, "The Tonight Show" beckoned in 1962, and the rest is TV and pop culture history. But it wasn't all smooth sailing. There were the jokes at Mr. McMahon's expense about his fondness for the bottle -- "Ed only drinks on special occasions ... like when he sees wall-to-wall carpeting."

Yesterday, the blogs were posting a famous 1977 episode in which an intoxicated Mr. McMahon nearly implodes on the air while a desperate, uncomfortable Mr. Carson tries to cover for him.

Post-Johnny Carson, Mr. McMahon would remain in the public eye -- somewhat cheesily -- as the host of "Star Search," and the guy who showed up at your door with the winning check for American Family Publishers. As recently as January, he was hawking a cash-for-gold business during the Super Bowl.

He also struggled in recent years with lawsuits and financial problems.

He was parodied mercilessly by Phil Hartman on "Saturday Night Live" -- "You are CORRECT, sir!" -- but his legacy also lives on in the comfortable banter between Paul Shaffer and David Letterman or Andy Richter and Conan O'Brien.

In Answers.com, sidekicks are described as those who "frequently serve as an emotional connection, especially when the hero is depicted as detached and distant, traits which would normally generate difficulty in making the hero likable."

Mr. McMahon performed that crucial function for one of the great comedians of the 20th century, who once complained on the air about his reputation, only to have Mr. McMahon come back with the perfect sidekick's response.

"Ed, I'm so tired of the same old crap: people telling me, 'You're cool and aloof.' They always want to know why I'm cool and aloof instead of hot and stooped. You've known me for 18 years. Am I cool and aloof?"

To which Mr. McMahon replied: "No, my lord."