Pendleton Ward
Lumpy Space Princess (voice) (26 eps)
Olivia Olson
Marceline the Vampire Queen (voice) (26 eps)
Jeremy Shada
Finn the Human (voice) (26 eps)
John DiMaggio
Jake the Dog (voice) (26 eps)
Tom Kenny
Ice King (voice) (26 eps)
Hynden Walch
Princess Bubblegum (voice) (26 eps)
Niki Yang
BMO / Lady Rainicorn (voice) (26 eps)
Polly Lou Livingston
Tree Trunks (voice) (26 eps)
Ava Acres
Young Marceline (voice) (1 eps)
Eric Bauza
Buttersotch Butler (voice) (1 eps)
Kyla Rae Kowalewski
Me-Mow (1 eps)
'Weird Al' Yankovic
Banana Man (1 eps)
Neil Patrick Harris
Prince Gumball (1 eps)
Grey DeLisle
Ice Queen (1 eps)
Madeleine Martin
Fionna (1 eps)
Roz Ryan
Cake (1 eps)
Justin Roiland
Earl of Lemongrab (voice) (1 eps)