Ben 10: Ultimate Alien (TV) Cast
The cast of Ben 10: Ultimate Alien. Updated on June 19, 2025.
59 actors
Yuri Lowenthal
as Ben Tennyson (voice) (52 episodes)

Yuri Lowenthal voices Ben Tennyson, the young hero with the ability to transform into various aliens.

Ashley Johnson
as Gwen Tennyson (voice) (52 episodes)

Ashley Johnson provides the voice for Gwen Tennyson, Ben's intelligent and resourceful cousin.

Greg Cipes
as Kevin Levin (voice) (52 episodes)

Greg Cipes voices Kevin Levin, a former foe turned ally with the power to absorb materials around him.

Dee Bradley Baker
as Humungosaur (voice) (52 episodes)

Dee Bradley Baker voices Humungosaur, one of Ben's alien transformations known for its strength and size.

Chris Pratt
as Cooper (voice) (2 episodes)

Chris Pratt lends his voice to Cooper, a skilled young technician and ally of Ben.

Powers Boothe
as Sunder (voice) (1 episode)

Powers Boothe voices Sunder, a formidable bounty hunter in the series.

Peter Stormare
as King Xarion / King Viktor (voice) (1 episode)

Peter Stormare provides the voice for King Xarion and King Viktor, characters with regal authority and ambition.

Beth Littleford
as Sandra Tennyson (voice) (1 episode)

Beth Littleford voices Sandra Tennyson, Ben's caring and supportive mother.

Greg Ellis
as Dagonet / Reporter Chet Rigby (voice) (1 episode)
Scott Menville
as Jimmy Jones (voice) (3 episodes)

Scott Menville voices both Jimmy Jones and J.T., among other characters, contributing to the series' engaging character dynamics.

J.K. Simmons
as Magister Gilhil / Plumber (voice) (1 episode)
Fred Tatasciore
as Foreman / Surgeon / Hammer (voice) (1 episode)
Nicholas Guest
as Simons / Worker / Guest (voice) (1 episode)
Peter MacNicol
as Oliver / Forever Knight #1 (voice) (2 episodes)
Matt Levin
as Cash (voice) (1 episode)
Tara Strong
as Serena / Young Ben Tennyson (voice) (1 episode)
Xander Berkeley
as Warden Morgg / Trukk (voice) (1 episode)
Kevin Michael Richardson
as Magister Pyke (voice) (1 episode)
Brian George
as Victor Valadis / Janitor (voice) (1 episode)
Miguel Ferrer
as Magister Hulka / Alpha #4 (voice) (1 episode)
Rob Paulsen
as Technician / Rhomboid Vreedle / Engineer #2 (voice) (1 episode)
Charlie Schlatter
as Tack / Plumber (voice) (1 episode)
Olivia Hack
as Emily (voice) (1 episode)
Jason Marsden
as Antonio (voice) (1 episode)
Paul Eiding
as Max Tennyson / Guard #1 / Guard #2 (voice) (7 episodes)
David McCallum
as Professor Paradox (voice) (3 episodes)
Juliet Landau
as Natalie Tennyson / Melinda (voice) (3 episodes)
James Arnold Taylor
as Announcer / Fake Vilgax / Fridge (voice) (1 episode)
Adam Wylie
as Pierce / Forever Knight #3 (voice) (1 episode)
Molly C. Quinn
as Eunice / Computer (voice) (2 episodes)
Diedrich Bader
as Simian (voice) (1 episode)
Jon Polito
as Mizaru (voice) (1 episode)
Alexander Polinsky
as Argit (voice) (4 episodes)
Dwight Schultz
as Dr. Animo / Teacher #2 (voice) (2 episodes)
Tia Texada
as Elena Validus (voice) (2 episodes)
Keone Young
as Julie's Dad / Repair Man / Cop (voice) (1 episode)
Yeni Alvarez
as Dr. Borges (voice) (1 episode)
Bill Mumy
as Agent Bryson (voice) (1 episode)
Vicki Lewis
as Agent Locke (voice) (1 episode)
Peter Renaday
as Sir George (voice) (5 episodes)
Diane Delano
as Ma Vreedle / Pretty Boy Vreedle (voice) (1 episode)
Jeff Bennett
as Pops Vreedle / Jailer (voice) (1 episode)
Robin Atkin Downes
as Sir Cyrus / Additional Voices (voice) (2 episodes)
Richard Doyle
as Driscoll / Additional Voices (voice) (2 episodes)
Khary Payton
as Hex (voice) (1 episode)
Kari Wahlgren
as Charmcaster (voice) (4 episodes)
Christopher McDonald
as Captain Nemesis (voice) (2 episodes)
Wil Wheaton
as Mike Morningstar / Darkstar (voice) (3 episodes)
Marianne Muellerleile
as Maureen (voice) (1 episode)
Tara Platt
as Jennifer Nocturne (voice) (2 episodes)
Danny Jacobs
as Captain / Police Dispatch / Dr. Pervis (voice) (1 episode)
Patrick Cavanaugh
as Winston / Esoterica / Additional Voices (voice) (3 episodes)
James Remar
as Vilgax (voice) (5 episodes)
John DiMaggio
as Aggregor (voice) (5 episodes)
Jim Piddock
as King Urien / Color Commentator / Chair Umpire (voice) (1 episode)
Vyvan Pham
as Julie Yamamoto / Computer Voice (voice) (5 episodes)
Zeno Robinson
as Alan Albright / Heatblast (voice) (2 episodes)
Tress MacNeille
as Zennith (voice) (1 episode)
Sean Donnellan
as Ben 10,000 / Eon (voice) (1 episode)
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