Ben Diskin

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

Lauren Tom

Kuki 'Numbuh 3' Sanban (voice)

Dee Bradley Baker

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

Cree Summer

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

Jason Harris

Chad Dickson (voice)

Grey DeLisle

Crazy Old Cat Lady/Gramma Stuffum (voice)

Jeff Bennett

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

Jennifer Hale

Fanny 'Numbuh 86' Fulbright / Computer (voice)

Mark Hamill

Stickybeard (voice)

Tom Kenny

Knightbrace / Mr. Wink (voice)

Maurice LaMarche

Father (voice)

Matt Levin

Patton 'Numbuh 60' Drilovsky (voice)

Frank Welker

Monty Uno (voice)

Neil Ross

Grandfather (voice)

Daran Norris

Count Spankulot (voice)

Rachael MacFarlane

Rachael T. 'Numbuh 362' McKenzie (voice)