Nick Kroll voices the character based on himself in Big Mouth, but Andrew has a different voice actor, with his real-life counterpart only serving as writer and producer – here’s why. Animated TV shows for adults have had a good run in recent years in the world of streaming, and among those is Big Mouth, created by Andrew Goldberg, Nick Kroll, Mark Levin, and Jennifer Flackett. Big Mouth made its debut on Netflix in 2017 and has been so well-received by critics and viewers that it was renewed through to a sixth season.
Big Mouth follows a group of teens as they deal with puberty and everything that comes with it with the help of their Hormone Monsters, who most of the time only end up creating more problems. Big Mouth has been praised for its humor and its approach to topics that are often considered taboo, for its self-awareness, and for how it references real-life brands, people, social issues, and more. One of the main reasons why Big Mouth has resonated with the audience is because it's based on Kroll and Golberg’s lives, as they have been best friends since childhood and had very different pubertal experiences. As a result, Nick Birch is based on Kroll’s journey, while Andrew Glouberman is the series’ version of Goldberg.
In addition to writing and producing, Nick Kroll lends his voice to his Big Mouth counterpart (and his adult version, Nick Starr) and many other characters, most notably Maury (Andrew and Matthew’s Hormone Monster), Coach Steve, and Lola Ugfuglio Skumpy. Andrew, on the other hand, is voiced by John Mulaney, who has also voiced Mint, Grandpa Andrew, Babe the Blue Ox, and Detective Florez. It’s inevitable to wonder, then, why Nick Kroll voices himself in Big Mouth but Goldberg doesn’t, but the answer is a lot simpler than you might think.
The reason for Andrew Goldberg not being the voice of Andrew Glouberman in Big Mouth like Nick Kroll is of Nick Birch is simply because he’s not an actor like the rest of the cast. Goldberg is a writer and producer, and aside from Big Mouth, he wrote for Family Guy (which he also produced at some point), the videogames Family Guy: The Quest for Stuff and Family Guy Online, and the shorts Seth & Alex’s Almost Live Comedy Show and Seth MacFarlane’s Cavalcade of Cartoon Comedy. His only acting role so far is as “Man Handing Bryan Cranston Emmy” in Family Guy’s episode “Herpe, the Love Sore”, but it was a very small one, so much that it was uncredited. On the other hand, John Mulaney is an actor and comedian, who aside from Big Mouth’s Andrew, voiced Peter Porker/Spider-Ham in Spider-Man: Into the Spider-Verse. Mulaney is also a close friend of Kroll, having worked together in Kroll Show and Oh, Hello on Broadway. With that in mind, it’s not surprising that he was brought in to take part in Big Mouth, and he has proven to be the perfect voice for Andrew.
Although Big Mouth has already gone through a recast with Missy, originally voiced by Jenny Slate and now by Ayo Edebiri, it’s highly unlikely Andrew Goldberg will take over the role of Andrew Glouberman at some point, though that doesn’t mean that Andrew isn’t a reflection of him. Nick Kroll and Andrew Goldberg will continue telling their stories and more through the characters in Big Mouth in the upcoming seasons, while John Mulaney will keep on voicing Andrew, and that’s part of the balance that has made the series work so well.