30 years at the top is pretty tough to beat, but its also true that he pretty much had the late night airwaves to himself for much of that period. He put both his guests and viewers at ease in a way that made him a comfortable household figure. But his act likely wouldn't have cut it in today's hyper-clatter of television and popular culture. He almost stuck around too long, but saw the writting on the wall and bowed out gracefully. It was indicative of how he handled himself during his entire career.

It's hard to decide who deserves the number one spot on any "all time" list, but it's hard to put up an argument against Johnny Carson for number one on this one.

Yes, he was late night, but he was a power house in late night, drawing more viewers than a lot of prime time programs. When NBC was floundering in the prime time ratings in the 70s and early 80s, it was Carson in his late night slot that provided a bright spot on their schedule.

Countless comedic careers were made or broken on Carson's show. A comedian just getting a few minutes of his act on Carson's show got them noticed, if they made Carson laugh it lead to work, and if they were among the chosen few that were asked to sit down they became stars. David Letterman, George Carlin, Eddie Murphy, Bill Cosby, Jerry Sienfeld, Paul Rieser, and Freddie Prinze are just a few of the names that owe a large chunk of their success to their Tonight Show appearance.

There is also the fact that he did it for so long. When he started the show was aired in black and white, John Kennedy was president, man had not yet walked on the moon, and The Beatles had not yet made their first appearance in the United States. When he signed off for the last time almost 30 years later his ratings had indeed fallen for various reasons, but he was still an influential force on television.

He was a connection between the old guard and the young lions, and earned respect from both. Certainly an important figure in television history. 

Of, course, people didn't have sex until after they watched Carson. Funny and lovable.

He is what all late night hosts aspire to be.

Insanely self-important. . .quite dated and doesn't resonate with different generations- but you can't deny this old fart his due. . .Carson is a huge TV icon even though he's been off the air for quite some time. . .

Johnny was a man of great charm and wit. I looked forward to staying up late in the summer time as a teenager to watch The Tonight Show. There is no way to replace a man of his stature.

Was not surprised to see Johnny Carson as number one. he has been in tV since the 1050s.Even though he was not the first late night talk show host, he made a huge mark on talk shows. he was perfect in his job. when you look at all the failed talk shows. and he was on for close to 30s years, that is remarkable.

Loses a star only for being on late night. A true televeision icon needs to be on air when a broader audience can watch.