On Sept. 27, 1954, "The Tonight Show" debuted on NBC. We take a look back at one of the longest running shows on television. On Sept. 27, 1954, \u201cThe Tonight Show\u201d debuted on NBC. We take a look back at one of the longest running shows on television.The first \u201cTonight Show\u201d (then called \u201cTonight Starring Steve Allen\u201d) featured announcer Gene Rayburn and bandleader Skitch Henderson. The show had a runtime of 90 minutes and many elements were remarkably similar to today\u2019s, as the format included an opening monologue, celebrity interviews and comedic bits that sometimes took place outside the studio. It was first hosted by Steve Allen, who also hosted \u201cThe Steve Allen show\u201d on Sunday nights, going head-to-head with Ed Sullivan.Jack Paar took over in July of 1957, and the show became one of the first TV programs regularly taped in color. Paar was the first to introduce the idea of a guest host, and one of them he brought into America\u2019s homes was none other than Johnny Carson. Paar walked off the show when censors cut a joke he made about a \u201cwater closet,\u201d before returning nearly a month later. When he left the show for good in 1962, Groucho Marx and Mort Sahl were among the guest hosts who took over until a permanent replacement could be found. Paar often featured personalities who weren\u2019t necessarily there to promote anything. Because NBC\u2019s policy was to re-use videotape, almost none of Jack Paar\u2019s \u201cTonight Show\u201d work survives.Johnny Carson took over in 1962 and hosted the show for the next 30 years. Ed McMahon appeared as his sidekick for the duration of Carson's run. The format of Carson\u2019s show remains today, with a monologue of one-liners, the use of sketch comedy, and appearances by guests looking to plug their latest film, record, book, or TV show. Carson created a number of long running characters and sketches, including the pun-happy Carnac the Magnificent and ridiculous product pitchman Art Fern. Among his many guest hosts, some of the most frequent were Joey Bishop, Joan Rivers, Bob Newhart, David Letterman, and Jay Leno. The guests for Carson\u2019s final show, aired May 21, 1992, were Robin Williams and Bette Midler.Jay Leno is the second-longest-serving host after Carson, taking over May 25, 1992. Branford Marsalis was the original bandleader for Leno, but left in 1995 and was replaced by guitarist Kevin Eubanks. He too, bowed out in 2010, and the reins were handed over to Ricky Minor. Nominated for only one Emmy award since Leno took over hosting duties, the show has never been a critical darling.And then there was the whole Conan O\u2019Brien kerfuffle in 2009, which saw O\u2019Brien take over the show as agreed upon by Leno back in 2004. Leno was instead given a prime-time slot, but he failed to attract an audience. NBC were also disappointed with O\u2019Brien\u2019s late night viewership, and wanted to push his show later in the evening to make way for a new Leno time slot. O\u2019Brien refused, and following lots of media campaigning and public support, eventually bowed out, leaving the much-criticized Leno free to take back his old job. (He's since been replaced by Jimmy Fallon.)With all the changes in television, it's hard to say whether the show will still be around another half century from now, but it can be proud of its legacy of entertaining America's night owls.