A gap-toothed sardonic TV host with a flair for improvisation, David Letterman has taken a place as one of the kinds of late night television. While he was once seen as the apparent heir to Johnny Carson at NBC (where he spent much of the 1980s as writer and host of "Late Night with David Letterman"), the Indiana native surprisingly wasn't tapped to replace Carson when he retired. A bit peeved, Letterman accepted an offer from rival network CBS and since August 1993 had been ensconced as the host of "The Late Show with David Letterman", an NYC-based talk/variety series that has been popular with audiences and Emmy voters. With his "patented platypus grin" and a voice "as gracefully modulated and wickedly bland as that of a hip, small town jockey reading a mortuary commercial" (according to critic Richard Corliss), Letterman relies on an audience familiar with TV's pretensions in order to slyly poke fun at both these conventions and the society endangering them.

After graduating from Ball State in Indiana with a degree in radio and TV, Letterman took a job with a local TV station where, over the next few years, he hosted a children's program and a late night movie and worked as a news anchor and weather announcer. Reportedly his superiors were not pleased when, on the air, he congratulated a tropical storm on being upgraded to a hurricane.

Moving to L.A. in 1975, Letterman worked the stand-up comedy circuit and also sold material to the sitcom "Good Times" and to "The Paul Lynde Comedy Hour." Stints as a regular on "The Starland Vocal Band" (CBS, 1977) and Mary Tyler Moore's variety series, "Mary" (CBS, 1978), did not further his career, but his appearances on the "The Tonight Show" did. Letterman soon became Johnny Carson's regular host and in 1980 was given a chance to host a daytime comedy/variety program, "The David Letterman Show." Although the show lasted only three months, it was well-received critically and even garnered a handful of Daytime Emmy Awards. The powers at NBC realized that Letterman's quirky humor might be better suited to a younger, wilder, wee-hours set than it was to those who had just awakened to face another day.

With such hilarious regular featured as "Viewer Mail", "Tonight's Top 10", and "Stupid Pet Tricks", Letterman regularly broke the fourth wall of his performance space (witness the "Late Night Thrill-Cam") and addressed the medium of TV itself to a greater degree than his fellow talk show hosts. An heir to Ernie Kovacs, Letterman, whether bantering with sidekick Paul Shaffer (leader of "The World's Most Dangerous Band"), dropping objects off buildings, or launching his Velcro-clad body onto a wall and sticking there, had been unafraid to laugh at his failed jokes or to become a somewhat acquired taste. Guests on his show have had to attune themselves to his sometimes brilliant if often corrosive humor: Terri Garr showering on the set, hobbyists who save snowballs from each winter or dress parrots like Cyndi Lauper have fared well, though Nastassja Kinski stormed off the set when Letterman kept mocking her standing-on-end hairdo. The series had remained popular with Emmy voters garnering several awards, including the top prize as Outstanding Variety, Music, or Comedy Series in 1994 and consecutively in 1998, 1999, 2000, and 2001.

Letterman also used his production deal to develop new prime time series for CBS: the biggest hit to emerge from his Worldwide Pants banner was "Everybody Loves Raymond" (1996- ) starring comedian Ray Romano. And while NBC may not have tapped him to host "The Tonight Show," the network didn't bear any grudges as it aired the Letterman-produced series "Ed" (2000- ), a quirky comedy-drama about a man who returned to his hometown to operate a bowling alley after his marriage fails.

Letterman was a professional workhorse who was known for never missing a show until the year 2000, when the host had to undergo emergency bypass surgery, but friends of the show such as Julia Roberts and Regis Philbin stepped in to pinch-hit for him while he recovered; he was briefly sidelined again in 2003 with a case of shingles as stars like Bruce Willis, Bonnie Hunt, Vince Vaughn, Bill Cosby and bandleader Paul Shaffer tackled desk duty. Although known as a private person who rarely allows glimpse of his personal life and feeling, Letterman's proudest on-air moment may have come in the wake of the destruction of New York's World Trade Center when, after weeks off the air, he returned to the show and spoke compellingly and compassionately commiseration with anchormen Dan Rather.