The 77-year-old King was serenaded by Tony Bennett singing "The Best is Yet to Come" via remote from Louisiana.
King had announced this summer he would leave, ushered out by a struggling network. Once the dominant voice in cable television news, King has faded in a sea of sharp talkers. British talk-show host and "America's Got Talent" judge Piers Morgan takes over the 9 p.m. Eastern time slot in January.
Except for an agreement to host four specials a year at CNN, it's not clear what his work future holds. He's talked of doing comedy, or going back to some radio work.