Jack Paar, who pioneered the late-night talk show format on The Tonight Show, before bidding his viewers farewell while still in his prime, died Tuesday. He was 85.

Paar's family said he died in his sleep at his Greenwich, Conn., home as a result of a long illness.

Born in Canton, Ohio, in 1918, Jack Harold Paar left school at 16 to seek fame and fortune as a comic disc jockey.

Then, during the Second World War, he entertained troops in the South Pacific as a standup comedian in the U.S. Army special services.

By 1947, he was being touted as "the most promising star of tomorrow."

Over the course of the next decade, he had scored only modest successes, but that would eventually change.

"Jack invented the talk show format as we know it: the ability to sit down and make small talk big. I will miss him terribly," Merv Griffin told The Associated Press.

Though his name may not be familiar to young fans of contemporary favourites Jon Stewart, David Letterman or Jay Leno, Paar's legacy is vivid for those with a longer memory.

"Not only was he a great friend, he was my beginning, just as he was everyone else's," Griffin said.

In July 1957, Paar took over hosting duties on NBC's flagging late-night show. Although his predecessor Steve Allen had been hosting a variety show, Paar tried something different.

He chose talk.

Viewers loved Paar's wit and wisecracks, and quickly developed the habit of staying up late to watch the show -- then chatting about it with others the next day.

Until 1962, when Johnny Carson took over The Tonight Show, Paar carved a lively and popular niche on the otherwise predictable TV landscape with his then-unique mixture of conversation and stand-up comedy performances.

He championed a variety of entertainers, helping boost the careers of Jonathan Winters, Bob Newhart, Carol Burnett, Woody Allen and Bill Cosby.

And he played host to a stream of high-profile guests. Among them, a pre-Muhammad Ali, Cassius Clay, and John F. Kennedy -- campaigning for the presidency in 1960.

That same year, Paar grabbed headlines when he announced he was leaving the show. The night before his declaration, the network had admonished Paar for an apparently obscene segment in which the initials "W.C." were mistaken for "wayside chapel" instead of "water closet."

His departure was shortlived, however. A month later, he was lured back to the hosting gig.

In his typically cheeky manner, Paar began his opening monologue: "As I was saying, before I was interrupted ..."

Two years later, Paar bowed out of The Tonight Show spotlight for real, trading his late night slot for a prime-time hour.

Three years later, with little fanfare, Paar bowed out of the TV game altogether.

At The Tonight Show, Paar was followed Johnny Carson.

"He was a unique personality who brought a new dimension to late night television," Carson said, explaining he was "very saddened" by the news.

Carson's successor Jay Leno also paid tribute.

"Jack set the bar and he set it very high," Leno said in a statement. "He will be sorely missed."

Paar had a prime-time talk show for three more seasons, then retired from TV in 1965. His family said the former television star had suffered a stroke about a year ago.