Kermit the Frog (voiced by Matt Danner) – A level-headed and good-hearted frog who enjoys acting out adventure and making music with his banjo. However, he can get flustered rather easily, usually by the antics of those around him. He is also the leader of the Muppet Babies.
Miss Piggy (voiced by Melanie Harrison) – A beautiful and glamorous yet temperamental and self-centered pig who considers herself a star and harbors a crush on Kermit. She mostly speaks in a high-pitched voice but would at times greatly deepen when she gets passionate or angry. She is best friends with Summer.
Summer Penguin (voiced by Jessica DiCicco) – A good-hearted and sweet-natured penguin from the South Pole who loves to make art. She is best friends with Piggy.
Miss Nanny (voiced by Jenny Slate) – The caretaker of the Muppet Babies who is only seen from the shoulders down. The pattern on her stockings changes to reflect relevant elements in the episode plot. Miss Nanny won a gold medal in a gymnastics discipline at the Sport-A-Thon.
Camilla the Chicken (vocal effects provided by Melanie Harrison) – A white chick and Gonzo's best friend who is involved with the Muppet Babies' activities.
Mr. Statler and Mr. Waldorf (voiced by Eric Bauza and Matt Danner respectively) – The neighbors of Miss Nanny who often comment about the Muppet Babies' activities from the balcony of their home.
Beaker (voiced by Matt Danner) – Bunsen’s assistant.
Dr. Teeth (performed by Bill Barretta) – The band leader of the Electric Mayhem. He appeared in a live-action transmission in "Muppet Rock" where he saw Animal perform backstage and is interested in having him join the Electric Mayhem. Animal turns him down for now as he needs to continue practicing.
Rowlf the Dog (voiced by Matt Danner) – A fun-loving and easygoing dog who loves to sing and make music, usually with his piano.
The Swedish Chef (voiced by Matt Danner) – A mock Swedish-speaking cooking prodigy.
Robin the Frog (voiced by Eric Bauza) – A small polliwog who is Kermit's nephew. He has a tail due to being in his tadpole state.
Scooter (voiced by Ogie Banks) – A young boy who wears a green and yellow track jacket.
Skeeter (voiced by Cree Summer) – Scooter's athletic twin sister who wears a sports-inspired purple jacket, a baseball-shaped watch, and pig tails.
Priscilla – One of Camilla's fellow chicks who is yellow.
Beep – One of Camilla's fellow chicks who is brown and makes the sound of a car horn instead of clucking.
Carlos (voiced by Todrick Hall) - A blue frog that appears in "Frogs of a Feather". In "Frog Scouts", Carlos becomes part of the Frog Scouts alongside Kermit and Robin.
Mr. Manny (voiced by Dulé Hill) - A friend of Miss Nanny. Like Miss Nanny, his head is never shown. Mr. Manny is known for his catchphrase where he states that a certain thing "is groovy" which is always accompanied by Mr. Manny doing horizontal gestures with his hands, bending his knees, and doing a motion that has him wiggle his hips. He is also shown to be a volunteer at the local library and the scout troop leader of the Frog Scouts.
Rozzie (voiced by Charlie Townsend) - A young koala who is Fozzie's adopted sister.