Late Night with Conan O'Brien is an American late-night talk show hosted by Conan O'Brien that aired 2,725 episodes on NBC between 1993 and 2009. The show featured varied comedic material, celebrity interviews, and musical and comedy performances. Late Night aired weeknights at 12:37 am Eastern/11:37 pm Central and 12:37 am Mountain in the United States.

O'Brien's Late Night debuted on September 13, 1993, with Andy Richter chosen as O'Brien's sidekick. The premiere episode featured John Goodman (who received a "First Guest" medal for his appearance), Drew Barrymore, and Tony Randall. The episode featured a cold open of O'Brien's walk to the studio with constant reminders that he was expected to live up to Letterman, parodying a popular sentiment expressed in the media at the time. After seeming to be unaffected by the comments, O'Brien arrives at his dressing room and cheerfully prepares to hang himself. However, a warning that the show is about to start causes him to abandon his plans.  O'Brien's inexperience was apparent and the show was generally considered mediocre by critics in terms of the host's ability. The Chicago Sun-Times' Lon Grankhe called O'Brien "nervous, unprepared and generally geeky" and Tom Shales wrote "As for O'Brien, the young man is a living collage of annoying nervous habits. He giggles and titters, jiggles about and fiddles with his cuffs. He has dark, beady little eyes like a rabbit. He's one of the whitest white men ever." (O'Brien wrote for The New York Times a satirical review of the first episode the day it aired titled "O'Brien Flops!", in which he told readers "Frankly, I was not impressed".) The originality and quality of the comedy, however, led by original head writer Robert Smigel, was widely praised. Although O'Brien benefited by comparison from the quick critical and commercial failure of the fellow new late-night The Chevy Chase Show, NBC only offered short-term contracts, 13 weeks at a time and once for six weeks, as widely reported by the press at the time. O'Brien was reportedly almost fired at least once in this period, but NBC had no one to replace him. According to Smigel, "We were basically canceled at Conan, and then they changed their minds in August of '94, gave us a reprieve."  According to O'Brien a network executive told him, in regards to Andy Richter, he'd "never succeed until I 'got rid of that big fat dildo.' That was the tone of the conversations between us and the network." It was widely expected that the host of Talk Soup, Greg Kinnear would take over the role, but Kinnear turned down the opportunity and decided to pursue a career in acting. Stars like Tom Hanks agreed to appear on Late Night, which boosted audience awareness. Even Letterman, who admired O'Brien's comic sensibility, appeared as a guest to register his support. O'Brien's performance style improved through experience and he began to receive more favorable reviews and ratings the following year. With the ratings gradually improving over the course of two years, Late Night reached a new level of critical and commercial success in 1996. Tom Shales officially recanted his previous critical review with the headline "I was wrong", and O'Brien received his first Emmy writing nomination, which he has gone on to receive every year since.

When did it debut?
O'Brien's Late Night debuted on September 13, 1993,