Dwayne Johnson as Krypto the Superdog (voice)

Kevin Hart as Ace the Bat-Hound (voice)

John Krasinski as Clark Kent / Superman (voice)

Keanu Reeves as Bruce Wayne / Batman (voice)

Kate McKinnon as Lulu (voice)

Vanessa Bayer as PB (voice)

Natasha Lyonne as Merton (voice)

Diego Luna as Chip (voice)

Jameela Jamil as Diana Prince / Wonder Woman (voice)

Marc Maron as Lex Luthor (voice)

Dascha Polanco as Jessica Cruz / Green Lantern (voice)

Olivia Wilde as Lois Lane (voice)

Jemaine Clement as Arthur Curry / Aquaman (voice)

Daveed Diggs as Victor Stone / Cyborg (voice)

John Early as Barry Allen / The Flash (voice)

Ben Schwartz as Mark / Fire Guinea Pig (voice)

Thomas Middleditch as Keith / Ice Guinea Pig (voice)

Maya Erskine as Mercy Graves (voice)

Yvette Nicole Brown as Patty (voice)

Alfred Molina as Jor-El (voice)

Lena Headey as Lara (voice)

Keith David as Dog-El (voice)

Busy Philipps as Foofy Dog (voice)

Dan Fogler as Carl / Pilot / Racer (voice)

Winona Bradshaw as Whiskers (voice)

David Pressman as Corgi (voice)

Sam Levine as Waffles / Robot Guards (voice)

Jared Stern as Bathtub Guy / JLA Hotline (voice)

Michelle Morgan as Mech Suit (voice)

Amanda Ames as Guinea-Pigasus (voice)

Gavin McCrillis as Black Kitten (voice)