Main voices

Adam DeVine as Sam-I-Am, a hyperactive, playful, and happy-go-lucky enthusiast of green eggs and ham. He is Guy's best friend and Pam's son.

Michael Douglas as Guy-Am-I, a cantankerous, sardonic, and frustrated failed inventor who is revolted by green eggs and ham, despite never having eaten them. He is Sam's best friend, Michellee's husband and E.B.'s step-father, and Guy Jr.'s father.

Ilana Glazer as E.B. (Elanabeth) Weebie-Am-I, Michellee's 9-year-old daughter and Guy's step-daughter, also Sam's Best friend and Guy Jr.'s older maternal half-sister who's plucky, good-hearted, and adventurous with a kind heart.

Diane Keaton as Michellee Weebie-Am-I, E.B.'s and Guy Jr.'s overprotective mother and Guy's wife also Sam's Best friend.

Keegan-Michael Key as the Narrator, the voice who tells the stories of the show.

Season 1

Eddie Izzard as Hernvick Z. Snerz, an arrogant businessman who wants to capture Mr. Jenkins.

Rob Paulsen voices Little Snerz.

Jeffrey Wright as McWinkle, a deadly serious member of "the BAD GUYS" Despite his gruff persona, he is shown to deeply care for the animals he is assigned to protect (the acronym BAD GUYS ironically stands for "Bureau of Animal Defense Glurfsburg Upper Yipville Section").

Jillian Bell as Gluntz, McWinkle's optimistic and easily excited rookie partner. She returns in season 2 as a fully realized B.A.D.G.U.Y.S. agent. In Season 2, Bell also voices Hayzel, a perky (but also tough-as-nails) Zookian guard, who captures Guy and E.B. and interrogates the two in Season 2, Episode 3.

John Turturro as The Goat, a brutal bounty hunter goat sent by Mr. Snerz. He speaks with a tough Spanish accent.

Dee Bradley Baker as the vocal effects of Mr. Jenkins (credited as "Chickeraffe"), an energetic chickeraffe (chicken-giraffe hybrid) who Guy and Sam protect. Baker also does the vocal effects of the Giroosters, Squails, Camelopes, Dolphocudas, and all the animal hybrids within the show.

Fred Tatasciore as Yes-Man, Mr. Snerz's sniveling assistant. Tatasciore also voices Jeremy, Hayzel's "Lie Detector" who helps interrogate Guy and E.B. in Season 2, Episode 3. He also voices Dark, the shadowy figure, who shares his riddles speaks in low voice.

Tracy Morgan as Michael (credited as "Fox"), an eccentric fox who is obsessed with green eggs and has a crush on a green chicken named Sandra.

Daveed Diggs as Squeaky (credited as "Mouse"), an imprisoned mouse who wants to feed his wife and daughter he himself is a cross-parody of the character "Jean Valjean" from Les Misérables and Diggs' own characterization of Marquis de Lafayette from Hamilton. He speaks with a French accent, though most are unable to understand his language.

Billy Eichner as Captain Bigman, McWinkle and Gluntz's boss. Eichner also voices Boat, a red and white ferry, speaks in deep voice.

David Kaye, Nika Futterman, Keith Ferguson as Cronies (Crony 3 is credited as "Big Green Crony").

Rob Paulsen as Pool Shark

David Kaye as Joaquin Furmano, a news reporter. Kaye also voices Train, a mighty red diesel locomotive, takes with his friends to Meepville, speaks in deep voice.

Grey DeLisle as Rain, a female raindrop with a melodic voice. DeLisle also voices Ty, Guy-Am-I's niece, a member of Am-I Family.

Chris Diamantopoulos as Bean Counter, who works in SnerzCo. Diamantopoulos also voices Box, a cardboard box with a childlike, playful voice, creates inventions and gizmos.

Brad Abrell as House, a talking cozy house, speaks in warm voice.

Keith Ferguson as Car, a red and black automotive with a deep, playful voice. Which Sam and Guy steals him from a B.A.D.G.U.Y.S. agents’ talking car.

Season 2

Patricia Clarkson as Pam-I-Am, Sam's long-lost biological mother and an international super spy working for Yookia to retrieve a dangerous substance known as the Moo-Lacka-Moo.