| Person | Type | Job | Role(s) | Episodes |
|---|---|---|---|---|
 David Letterman | Crew | Writing | Writer | 4252 |
 Eric Stangel | Crew | Production | Executive Producer, Producer | 181 |
 Félim Gormley | Crew | Sound | Musician | 219 |
 Al Pacino | Cast | Actor | Himself | 1 |
 Alicia Keys | Cast | Actress | Self | 1 |
 Bill Wendell | Cast | Self - Announcer (voice) | 439 | |
 Bruce Willis | Cast | Actor | Self | 1 |
 Christopher Walken | Cast | Actor | Self | 1 |
Cody Arens | Cast | Actor | Self | 1 |
 Dana Carvey | Cast | Actor | Self | 1 |
David Letterman | Cast | Actor | Self - Host | 4252 |
 Eric Leeds | Cast | Actor | 1 | |
 Eric Stonestreet | Cast | Actor | Self - Guest | 1 |
 Gary Sinise | Cast | Actor | Self - Guest | 1 |
 Jeff Altman | Cast | Actor | Self | 1 |
 Julianna Margulies | Cast | Actress | Self - Guest | 1 |
 Julio Iglesias | Cast | Actor | Self - Musical Guest | 1 |
 Lisa Howard | Cast | Actress | Lt. Genevieve Marshall | 1 |
 Maggie Gyllenhaal | Cast | Actress | Herself | 1 |
 Melissa McCarthy | Cast | Actress | Self | 1 |
 Neil Young | Cast | Actor | Himself | 1 |
 Paul Morrissey | Cast | Actor | Self | 1 |
 Paul Rudd | Cast | Actor | Self | 1 |
 Prince | Cast | Actor | 1 | |
 Rachelle Lefevre | Cast | Actress | Self | 1 |
 Regis Philbin | Cast | Actor | Self | 1 |
 Rhonda Smith | Cast | Actress | 1 | |
 Ricki Lake | Cast | Actress | Self - Guest | 1 |
 Scarlett Johansson | Cast | Actress | Self | 4 |
 Shep Gordon | Cast | Actor | Self | 1 |
 Susan Sarandon | Cast | Actress | Self | 1 |
 Adam Levine | Cast | Actor | Self | 1 |
 Emily Blunt | Cast | Actress | Herself | 1 |
 Eric Ripert | Cast | Actor | Self - Guest | 1 |
 Janelle Monáe | Cast | Self | 1 | |
 Miles Kath | Cast | Actor | Young Lettermen | 1 |
 Olivia Wilde | Cast | Actress | Self | 1 |
 Tatiana Maslany | Cast | Actress | Self | 1 |
 Tom Mison | Cast | Actor | Self - Guest | 1 |
 Whitney Cummings | Cast | Actress | Self | 1 |
 Ellie Kemper | Cast | Actress | Self | 1 |
 Lady Gaga | Cast | Actress | Self - Guest | 1 |
 Sam Smith | Cast | Self | 1 | |
 Choi Soo-young | Cast | Actress | Herself | 1 |
 Taylor Swift | Cast | Actress | Self - Musical Guest | 1 |
 Harry Styles | Cast | Actor | Himself | 1 |
 Hyoyeon | Cast | Actress | Herself | 1 |
 Jessica Jung | Cast | Actress | Herself | 1 |
 Liam Payne | Cast | Actor | Himself | 1 |
 Louis Tomlinson | Cast | Actor | Himself | 1 |
 Niall Horan | Cast | Actor | Himself | 1 |
 Seohyun | Cast | Actress | Herself | 1 |
 Sunny | Cast | Actress | Herself | 1 |
 Taeyeon | Cast | Actress | Herself | 1 |
 Tiffany Young | Cast | Actress | Herself | 1 |
 Yoona | Cast | Actress | Herself | 1 |
 Kwon Yu-ri | Cast | Actress | Herself | 1 |
 Zayn Malik | Cast | Actor | Himself | 1 |
 Paul Shaffer | Cast | Actor | Self -Musical Director | 4252 |
Edd Hall | Cast | Actor | Various VOs (voice) | 1 |
 Joe Seaward | Cast | Actor | Self - Musical Guest | 1 |
 Dave Bayley | Cast | Actor | Self - Musical Guest | 1 |
 Drew MacFarlane | Cast | Actor | Self - Musical Guest | 1 |
 Edmund Irwin-Singer | Cast | Actor | Self - Musical Guest | 1 |
 Angel Olsen | Cast | Actress | Self | 1 |
Morris Hayes | Cast | Actor | 1 | |
Kirk Johnson | Cast | Actor | 1 | |
John Grant | Cast | Actor | Self | 1 |
| Person | Type | Job | Role(s) | Episodes |
