Ben Diskin

as Nigel 'Numbuh 1' Uno / Hoagie Pennywhistle 'Numbuh 2' Gilligan Jr / Numbuh 101 (voice)

Lauren Tom

as Kuki 'Numbuh 3' Sanban (voice)

Dee Bradley Baker

as Wally 'Numbuh 4' Beatles / Mr. Fibb / Toilenator / Joaquin / Tommy Gilligan (voice)

Cree Summer

as Abigail 'Numbuh 5' Lincoln / Former Numbuh 11 - Cree Lincoln (voice)

Jason Harris

as Chad Dickson (voice)

Grey DeLisle

as Crazy Old Cat Lady/Gramma Stuffum (voice)

Jeff Bennett

as Mr. Boss / Mr. Fizz / Benedict Wigglestein (voice)

Jennifer Hale

as Fanny 'Numbuh 86' Fulbright / Computer (voice)

Mark Hamill

as Stickybeard (voice)

Tom Kenny

as Knightbrace / Mr. Wink (voice)

Maurice LaMarche

as Father (voice)

Matt Levin

as Patton 'Numbuh 60' Drilovsky (voice)

Frank Welker

as Monty Uno (voice)

Neil Ross

as Grandfather (voice)

Daran Norris

as Count Spankulot (voice)

Rachael MacFarlane

as Rachael T. 'Numbuh 362' McKenzie (voice)

Ogie Banks

as Sector Z Numbuh 0.1 - Bruce (voice)

Janice Kawaye

as Sonya - Number 83 / Lee - Numbuh 84 (voice)

Dave Wittenberg

as Numbuh Zero / Lenny - Sector Z Numbuh 0.4 (voice)

Cam Clarke

as Additional Voices (voice)

Candi Milo

as Additional Voices (voice)