David Michael Letterman -Late Night with David Letterman on NBC and Late Show with David Letterman on CBS

David Michael Letterman(DOB April 12, 1947)hosted the late night TV talk show for 33 years, beginning with the February 1, 1982, debut of Late Night with David Letterman on NBC and ending with the May 20, 2015, broadcast of the Late Show with David Letterman on CBS 

 

Bill Murray, who appeared on 'The Late Show with David Letterman' in 1982

 Late Night with David Letterman premiered in 1982 as the first incarnation of the Late Night Franchise and ran until 1993, when Letterman left NBC and moved to Late Show on CBS

The series was then reformatted as Late Night with Conan O'Brien with Jimmy Fallon later taking over from O'Brien as host. Late Night continues to air as of 2015 with Seth Meyers  as host.

The Late Show with David Letterman on CBS debuted on August 30, 1993 nd was produced by Letterman's production company, Worldwide Pants Incorporated and CBS TV Studios 

In 2014, Letterman announced his retirement and the final episode of the Late Show aired on May 20, 2015

In total, Letterman hosted 6,028 episodes of Late Night and Late Show, surpassing friend and mentor Johnny Carson as the longest-serving late night talk show host in American television history

 

John William "Johnny" Carson (October 23, 1925 – January 23, 2005) was an American television host, comedian, writer, producer, actor, and musician known for thirty years as host of The Tonight Show Starring Johnny Carson  (1962–1992)

Johnny Carson received six Emmy Awards, the Governor's Award, and a 1985 Peabody Award

Johnny Carson was inducted into the Television Academy Hall of Fame in 1987

Johnny Carson was awarded the Presidential Medal of Freedom in 1992  and

Johnny Carson received a Kennedy Center Honor in 1993.

Although his show was already successful by the end of the 1960s, during the 1970s Johnny Carson became an American icon and remained so until his retirement in 1992