Neil Patrick Harris

Dr. Horrible

Nathan Fillion

Captain Hammer

Felicia Day

Penny

Simon Helberg

Moist

Maurissa Tancharoen

Groupie #1

Jed Whedon

Bad Horse Chorus #2

Marti Noxon

Newswoman

Rob Reinis

Bad Horse Chorus #3 / Moving Guy

Otto Michael Penzato

Van Driver

Richard Partlow

Mayor

Stacy Shirk

Groupie #2

Steve Berg

Groupie #3

Lance Lanfear

Hawaiian Shirt Guy

Heather Black

Unfeeling Woman (uncredited)

David Fury

Newsman

Michael G. Canaan

Pink Pummeler

Douglas Petrie

Professor Normal

Drew Goddard

Fake Thomas Jefferson

Kate Danson

Tie-Die

Liz Vassey

Fury Leika

Nick Towne

Bad Horse Chorus #1

Athena Demos

Snake Bite