Will Forte as Doug Kenney

Domhnall Gleeson as Henry Beard

Martin Mull as Modern Doug

Neil Casey as Brian McConnachie

Jon Daly as Bill Murray

Nelson Franklin as P.J. O'Rourke

John Gemberling as John Belushi

Rick Glassman as Harold Ramis

Seth Green as Christopher Guest

Harry Groener as Harry Kenney

Max Greenfield as Chris Miller

Camille Guaty as Alex Garcia-Mata

Ed Helms as Tom Snyder

Thomas Lennon as Michael O'Donoghue

Joe Lo Truglio as Brad

Matt Lucas as Tony Hendra

Natasha Lyonne as Anne Beatts

Joel McHale as Chevy Chase

Annette O'Toole as Stephanie Kenney

Emmy Rossum as Kathryn Walker

Jackie Tohn as Gilda Radner

Matt Walsh as Matty Simmons

Finn Wittrock as Tim Matheson

Elvy as Mary Marshmallow

Frank Gingerich as Doug - Age 12

Morgan Gingerich as Doug - Age 12

David Wain as Interviewer

Ben F. Campbell as Harvard Jester

Jon Klaft as Preppy Student

Brad Morris as Peter Ivers

Carla Gallo as Lucy Fisher

Beau Bassewitz as Umpire

Rick Overton as First Publisher

Mark Metcalf as Second Publisher

David Krumholtz as Time-Life Publisher

Mitchell Hurwitz as Time-Life Publisher

Michael Colton as Art Director

John Aboud as Art Director

Michael Sherman as Ed Sullivan

Kerri Kenney as Sullivan Producer

Bob Stephenson as Construction Worker

Ellen Colton as Waitress

Liz Femi as Skeptical Black Woman

Chris Redd as Skeptical Black Man

Krister Johnson as Michael Gross

Peter Blake as Advertiser

Mike Park as Advertiser

Gregg Turkington as Advertiser

Michael Farrell as Radio Hour Pianist / Premiere Party Pianist

Adam Wade as Radio Hour Drummer / Premiere Party Drummer

Meera Rohit Kumbhani as Elaine

Jherek Bischoff as Lemmings Bass Player

Craig Wedren as Lemmings Piano Player

Sam Mickens as Street Musician

Armen Weitzman as Lorne Michaels

Lonny Ross as Ivan Reitman

Steven Sims as Stephen Furst

Brian Huskey as John Landis

Julian Wass as Premiere Party Guitar Player

Bo Boddie as Premiere Party Guitar Player

Rich Sommer as Harry Crane

Kate Simmons as Party Guest

Abigail Klein as Missy

Andrew Gray McDonnell as Michael O'Keefe

Erv Dahl as Rodney Dangerfield

Paul Scheer as Paul Shaffer

Martha Smith as Tour Guide

Hutch Barbeau as Studio Tour Kid

Matt Ballard as Bartender

Melissa Paulo as Room Service Waitress

Lindsey Kraft as Gwyneth Cravens

Christopher Arminio as National Lampoon Staffer (uncredited)

Bambadjan Bamba as Taxi Driver (uncredited)

James Bearb as Doug Niedermeyer (uncredited)

Garrett Boyd as Young Omega Chip Diller (uncredited)

Jack Andrew Cook as Dan Aykroyd (uncredited)

T.C. Daniels as Brian Doyle Murray (uncredited)

Gina Dunlap as Dancer (uncredited)

Paige Flannery as Stoned College Kid (uncredited)

Jake Jacobson as Ted Knight (uncredited)

Allyson Nicole Jones as Student (uncredited)

Sean Leo as Boyscout (uncredited)

Christina Miller as Funeral Guest (uncredited)

Lauryn Morse as Cheerleader Captain (uncredited)

Jeremey Penn as Daniel Kenney (uncredited)

Sandra Rosko as Stoner College Kid (uncredited)

Dallas Ryan as Sound Guy (uncredited)

Paul Rudd as "The Nobody" (uncredited)

David Sampen as Caddyshack Film Crew (uncredited)

Tim Seitter as Kroger (uncredited)

Vivienne Taylor as Toga Waitress (uncredited)