Mr. Grouper's voice actor, Tino Insana, is well known for playing Dr. Reginald Bushroot in Darkwing Duck, Uncle Ted in Bobby's World and Pig in Back at the Barnyard. He sounds similar to the late John Candy.
Mr. Grouper's singing voice, Chris Phillips, plays various background characters within the show. He was the original voice of Face, one of Nick Jr.'s previous mascots. He also does voiceover work for Nickelodeon's promos and commercials.