David Letterman hosts “The Late Show with David Letterman”

This is it for David Letterman. After more than three decades on late-night TV and more than 6,000 late-night broadcasts on his resumé, the legendary talk show host is signing off for good. Don't miss the final episode of "The Late Show with David Letterman" when it airs Wednesday, May 20, on CBS.

It all started in February 1982. Sort of. At least, that's when Letterman's late-night hosting career started. His actual journey to after-hours comedy started years earlier, after watching the late Paul Dixon's daily TV show.

"Without exaggeration, I was just out of college (in 1969), and I really didn't know what I wanted to do. And then, all of a sudden, I saw him doing it (on TV)," Letterman said in a 1997 interview with "The Cincinnati Enquirer." "And I thought: 'That's really what I want to do!'"

And do it he did. Starting out humbly as an anchor and weatherman on an Indianapolis TV station, Letterman quickly became known for his quirky and unpredictable on-air antics -- reporting on weather for fictitious towns, congratulating a tropical storm for being upgraded to a hurricane, and reporting that a state border had been wiped out, to name a few. He moved to Los Angeles in 1975, hoping to land a gig as a comedy writer, and found himself performing standup at The Comedy Store, the comedy club in West Hollywood that boasts an impressive list of alumni, including one Johnny Carson.

Flash forward a few years -- and quite a few writing and starring roles -- and Letterman's star had risen exponentially. He'd caught the eyes of scouts for Carson's "The Tonight Show Starring Johnny Carson" and very quickly developed a lasting relationship with the King of Late Night, becoming a regular guest as well as guest host on the iconic show. He soon landed his own hosting gig, a morning comedy show on NBC, and while the nature of his hosting duties have since changed, the rest -- as they say -- is history.

From "Late Night with David Letterman" on NBC, where he held down the fort for more than 11 years, to "The Late Show with David Letterman" on CBS, where he's been since August 1993, Letterman has spent the past 33 years as a staple on late-night television. His legacy is arguably unmatched, and where he once was looking up to comedic greats like Carson, he's now the person that is influencing other comedians.

"You see his influence in every talk show host -- Jon Stewart, Conan [O'Brien], [Stephen] Colbert, all those guys," Jimmy Kimmel ("Jimmy Kimmel Live") told "Rolling Stone" in 2011. "We're all 100 per cent guilty of stealing from Letterman. That show changed everything, and it changed the humor of the United States more than anything I can think of. We all got a lot cooler all of a sudden."

Johnny Carson and David Letterman as seen in “The Late Show with David Letterman”

He wasn't just effecting change amongst talk-show hosts, either. Letterman was forced to do something different on late-night TV, as Carson's production company had a lot of sway in regards to what "Late Night" could and couldn't do. Carson didn't want the two shows to overlap content, so Letterman was forced to get creative with his sketches and, more importantly, his guests. This mandatory change proved to be the best thing for Letterman, "Late Night" and eventually "The Late Show," and its effects are still prevalent today.

"He did the thing that everyone's tried to do since and has never done, which is to take the talk show form and redo it," said Jerry Seinfeld ("Seinfeld") in the same "Rolling Stone" piece. "The mindset was: 'We're tired of pretending there are no cue cards and no cameras and nothing's rehearsed. It's late, and we're going to take over this little piece of territory and do our own thing.' Now that mindset is everywhere."

It'll be tough for Letterman's replacement -- Emmy-winning, Grammy-winning and Peabody Award-winning comedian Stephen Colbert ("The Colbert Report") -- to fill the big shoes left by the 68-year-old Hoosier. But as Colbert said when it was first announced he'd take over "The Late Show" (which will premiere under Colbert's name in September), he couldn't be more thrilled to do it.

"Simply being a guest on David Letterman's show has been a highlight of my career," Colbert said in a news release. "I never dreamed that I would follow in his footsteps, though everyone in late night follows Dave's lead. I'm thrilled and grateful that CBS chose me. Now, if you'll excuse me, I have to go grind a gap in my front teeth."

It'll be very strange not seeing David Letterman on late-night TV. After an impeccable 33-year-run and with 6,028 talk show broadcasts under his belt, he's become a mainstay on the medium, revolutionizing modern talk shows and influencing the new generation of late-night hosts. Do not miss "The Late Show with David Letterman" when the legendary comedian signs off for the last time Wednesday, May 20, on CBS.