<Ul> <Li> Kevin Hart as George Beard, a fourth - grade student . He is Harold's best friend and writes stories for the comics he and Harold make . </Li> <Li> Thomas Middleditch as Harold Hutchins, a fourth - grade student . He is George's best friend and illustrates the comics he and George make . </Li> <Li> Ed Helms as Mr. Benjamin "Benny" Krupp / Captain Underpants, the mean - spirited principal of Jerome Horwitz Elementary School, who is hypnotized into becoming the superhero created by George and Harold . </Li> <Li> Nick Kroll as Professor Pee - Pee Diarrheastein Poopypants, Esq., a scientist angered after being constantly made fun of and not taken seriously for his name, who decides to take over the world to get rid of all laughter and captain underpants _́ s arch - nemesis . </Li> <Li> Jordan Peele as Melvin Sneedly, George and Harold's arch - nemesis, a child prodigy inventor; he becomes Prof. Poopypants' unwitting sidekick . </Li> <Li> Kristen Schaal as Edith, the shy school lunch lady and the love interest of Mr. Krupp . </Li> <Li> Dee Dee Rescher as Ms. Tara Ribble, the 4th - grade teacher (and George's new teacher when Mr. Krupp separates the boys). </Li> <Li> Brian Posehn as Mr. Rected, the guidance counselor (and Harold's new teacher when Mr. Krupp separates the boys). </Li> <Li> Mel Rodriguez as Mr. Morty Fyde, the science teacher who gets fired by Krupp and is replaced by Professor Poopypants . </Li> <Li> David Soren as Tommy, a boy who is seen frequently throughout the movie climbing into his own locker and shutting the locker door behind him . </Li> <Li> Susan Fitzker as Mrs. Dayken, George and Harold's kindergarten teacher and unintentionally made them laugh by mentioning Uranus </Li> <Li> Lynnanne Zager as Mrs. Beard </Li> <Li> Tiffany Lauren Bennicke as Sad Girl </Li> <Li> James Ryan as Mime </Li> <Li> Leslie David Baker as Officer McPiggly </Li> <Li> Sugar Lyn Beard as Goodie Two - Shoes Girl </Li> <Li> Lesley Nicol as Nobel Moderator </Li> <Li> Chris Miller as Nobel Audience Member </Li> <Li> Coco Soren as Balloon Girl </Li> </Ul> <Li> Kevin Hart as George Beard, a fourth - grade student . He is Harold's best friend and writes stories for the comics he and Harold make . </Li> <Li> Thomas Middleditch as Harold Hutchins, a fourth - grade student . He is George's best friend and illustrates the comics he and George make . </Li> <Li> Ed Helms as Mr. Benjamin "Benny" Krupp / Captain Underpants, the mean - spirited principal of Jerome Horwitz Elementary School, who is hypnotized into becoming the superhero created by George and Harold . </Li>

Who voices harold in the captain underpants movie