Jimmy Fallon will take over the late-night show after Leno leaves, and the show will be returning to New York, the network said.
"Congratulations Jimmy. I hope you're as lucky as me and hold on to the job until you're the old guy. If you need me, I'll be at the garage," Leno said in a statement.
In addition to the changes, "Saturday Night Live" producer Lorne Michaels will replace Debbie Vickers as executive producer of the show.
NBC has not yet announced what will replace Fallon's current show, "Late Night with Jimmy Fallon," in the 12:35 a.m. time period.
"I'm really excited to host a show that starts today instead of tomorrow," Fallon said in a statement.
Leno has hosted "The Tonight Show" since taking over for Johnny Carson in 1992.