The quarterback led the Baltimore Ravens to a 34-31 victory against the San Francisco 49ers on Sunday in Super Bowl XLVII in New Orleans. Flacco completed a remarkable postseason run with 11 touchdown passes and zero interceptions in four games. He is close to becoming a free agent.
Letterman asked the Super Bowl MVP if he had spoken to team owner Steve Bisciotti about a new contract.
"Well, you know, actually, I only talked to him a little bit before this game, but before the New England game, you know, he just came up to me and said, 'Listen, this is our time, and go get 'em. We have all the faith in you, and this is going to be your team for a long time,'" Flacco said.
Flacco said he turned down an extension offer from the Ravens last year.
"Well ... when I wasn't signing what they wanted me to sign, (Bisciotti) said, 'Listen, when the time comes, I mean, you come and beat on my desk,' and I said, 'All right, I'll take you up on that,' and I think the time has come."
Flacco did a morning press conference in New Orleans on Monday after winning the Super Bowl, then flew to Orlando to appear at Disney World, then flew to New York to do Letterman.
He must have been exhausted, but he only displayed his trademark Joe Cool demeanor as he calmly explained what it's like to be Ray Lewis' teammate and why playing quarterback in the NFL is probably not as hard as people think it is.
He closed his appearance by easily completing a short pass to Letterman near the audience.
The Associated Press contributed to this story.