David Michael Letterman is an American talk show host, comedian, and television producer. Letterman's ironic, often absurdist comedy is heavily influenced by comedians Steve Allen, Ernie Kovacs, and Johnny Carson.

Letterman was born in Indianapolis, Indiana. Letterman's father, Harry Joe Letterman, was a florist who passed away in 1974; his mother Dorothy, a Presbytarian church secretary, is a regular personality on his talk show. He has an older sister, Janice, and a younger sister, Gretchen. He graduated from Broad Ripple High School in Indianapolis and attended Ball State University, receiving a B.A. in telecommunications in 1969. At Ball State he was a member of the Sigma Chi Fraternity. He also began his broadcasting career at Ball State's student run radio station, WAGO - AM 570 (Now known as WCRD "Cardinal Radio Dave", 91.3). A rare aircheck of Letterman on WAGO can be heard here.

Letterman began work as a radio talk show host and on television as an anchor and weatherman for what became WTHR in Indianapolis. He received recognition for his unpredictable on-air behavior, which included erasing state borders from the weather map and predicting hail stones "the size of canned hams." One night he reportedly upset his bosses when he congratulated a tropical storm on being upgraded to a hurricane.

In 1975, Letterman moved to California with hopes of becoming a comedy writer and started writing material for sitcoms, such as Good Times. He also began performing stand-up comedy at The Comedy Store, a famed Los Angeles comedy club and proving ground for young comics.

Letterman had a stint as a cast member on Mary Tyler Moore's variety show Mary, a guest appearance on Mork & Mindy, and appearances on game shows such as The $20,000 Pyramid. His dry, sarcastic humor caught the attention of talent scouts for Johnny Carson's The Tonight Show, and starting in 1978, Letterman became a regular guest host for the show.

Letterman was given his own morning comedy show on NBC, The David Letterman Show. The show was a critical success, winning two Emmy Awards and receiving five nominations, but ended up being a ratings disappointment, and was cancelled after a brief run during the summer of 1980. However, NBC kept Letterman under contract, and in 1982, his Late Night with David Letterman debuted on the network.

Letterman's show, which ran late on weeknights immediately following The Tonight Show, quickly established a reputation as being edgy and unpredictable, and soon developed a cult following. The show was markedly different than the soft-sell talk-show competition, and Letterman the interviewer could be sarcastic and antagonistic, to the point that a number of celebrities have even stated that they were afraid of appearing on the show. Letterman's reputation as a testy interviewer was born out of moments like his verbal sparring matches with Cher, Madonna, and Shirley MacLaine.

The show often included quirky, genre-mocking regular features, such as "Stupid Pet Tricks", the Top 10 List, and a facetious letter-answering segment on Fridays. Other memorable moments included Letterman using a bullhorn to interrupt The Today Show TV program, which was on the air conducting a live interview at the time, announcing that he was not wearing any pants; interrupting Al Roker on the live local news by walking into the studio; and the outrageous appearances by comedian Andy Kaufman and comic book writer, Harvey Pekar. In one highly publicized appearance, Kaufman appeared to be slapped and knocked to the ground by professional wrestler Jerry Lawler. (Lawler and Kaufman's friend Bob Zmuda later revealed that the event was staged.) Letterman also made use of the Manhattan location of his NBC studio, often staging comedy bits on the streets and businesses surrounding the theater.

Letterman remained with NBC for eleven years. When Johnny Carson announced that he would retire in May 1992, a protracted, multi-lateral battle erupted over who would replace the long-time Tonight host. Eventually, executives at NBC announced Carson's frequent guest-host Jay Leno as Carson's replacement. Letterman, a protégé of Carson's and who had frequently credited Carson with boosting his career, was reportedly bitterly disappointed and angry at not having been given the Tonight Show job which he claimed to have been promised many years earlier. In 1993, after receiving advice from Carson, Letterman moved to CBS to host a new show, The Late Show with David Letterman. In 1996, HBO produced a made-for-television movie called The Late Shift, based on a book by Bill Carter, chronicling the battle between Letterman and Leno for the coveted Tonight Show hosting spot.

The Late Show competes in the same time slot as Leno's The Tonight Show. Letterman has garnered the critical and industry praise; his show has received 67 Emmy Award nominations, winning twelve times in his first twenty years in late night television. Leno consistently beats Letterman in the ratings, a lead that's grown over the years to two million viewers (5.8 vs. 3.8 million) as of 2003. Yet Letterman has consistently ranked higher than Leno in the annual Harris Poll of Nation's Favorite TV Personality; as of 2003 Letterman ranked third in that poll, behind Oprah Winfrey and Ray Romano, while Leno ranked ninth.

Letterman started his own production company, Worldwide Pants Incorporated, which produces his show and several others, including Everybody Loves Raymond, The Late Late Show with Craig Ferguson, and several critically acclaimed, but short-lived television series for Bonnie Hunt.

In January of 2000, Letterman underwent quintuple heart bypass surgery. During his recovery, friends of Letterman hosted reruns of the Late Show, including Drew Barrymore, Ray Romano, Robin Williams, Bill Murray, Kathie Lee Gifford, Regis Philbin, Charles Grodin, Julia Roberts, Bill Cosby, Bruce Willis, Jerry Seinfeld, Martin Short, Danny DeVito, Steve Martin and Sarah Jessica Parker. Upon his return to the show on February 21, 2000, Letterman brought onstage all of the doctors that had performed the operation, including Dr. O. Wayne Isom and physician Louis J. Aronne, who makes frequent appearances on the show. In an unusual show of emotion, Letterman was nearly in tears as he thanked the doctors. The episode earned an Emmy nomination.

On September 17, 2001, David Letterman was the first major American comedy performer to return to the television airwaves after the September 11, 2001 terrorist attacks. In his opening monologue, an uncharacteristically serious and very emotional Letterman struggled with the reality of the attacks and the role of comedy in a post-9/11 world, saying, "We're told that they were zealots fueled by religious fervor...religious fervor...and if you live to be a thousand years old will that make any sense to you? Will that make any goddamn sense?"

In March 2002, as Letterman's contract with CBS was expiring, ABC expressed the intention to offer Letterman the time slot for long-running news program Nightline with Ted Koppel, citing more desirable viewer demographics. This caused a minor flap that ended when Letterman re-signed with CBS and offered public apologies to Koppel.

In late February 2003, Letterman was diagnosed with a severe case of shingles. As a result, and for the first time since his bypass surgery, Letterman handed the reins of the show to several guest hosts including actor Bruce Willis, former professional tennis player John McEnroe, actor Luke Wilson, bandleader Paul Shaffer, comedian Bonnie Hunt, morning talk host Regis Philbin, rock musician Elvis Costello, Brad Garrett from Everybody Loves Raymond, comedians Tom Arnold, Bill Cosby, and Tom Green, as well as other prominent Hollywood performers.