Animated TV shows and movies have a history of developing live-action adaptations, but one member of the Griffin family makes it impossible for Family Guy to do so. Animation allows creators to design larger-than-life characters with distinctive physical features, which can sometimes translate to live-action well. Matthew Lillard's Shaggy in Scooby-Doo, Glenn Close's Cruella de Vil in 101 Dalmatians, and Jim Carrey's Grinch in How the Grinch Stole Christmas are all seamless examples of adapting a well-known animated character into human form. But not all animated characters are suitable for live-action.
Seth MacFarlane, the creator of Family Guy, American Dad!, and The Cleveland Show, has typically used animation in a way that still makes his characters look more-or-less human. MacFarlane's most famous family, the Griffins, could all be adapted into live-action without having to significantly change their look. That is with one major exception, Stewie Griffin.
Why Getting A Live-Action Stewie Right Is Impossible
Redditor mindtraveIIer created a fan poster of the Family Guy characters in human form, and Stewie Griffin looks terrifying. If Family Guy were to do a live-action adaptation, then from a purely aesthetic view Stewie would be the most difficult to get right because of his football-shaped head. There would be a temptation to give Stewie a more typical-looking head, but that would take away his most defining physical feature, and likely be met by backlash from Family Guy fans.
The smart-mouthed Stewie Griffin is known for doing things that a real 2-year-old cannot do but the medium of animation allows him to do so. From his over-the-top violence, construction of time machines, and musical numbers, Stewie's actions would be near impossible to adapt in live-action even with the use of special effects. Stewie's personality would also be problematic to re-create in live-action form because his sociopathic tendencies and advanced vocabulary make it impossible to cast a toddler as the youngest Griffin. CGI could be used to dub over a child actor but the physical acting required to match Stewie's personality would be difficult to bring to life.
Would The Rest Of Family Guy Suit A Live-Action Adaptation?
The human-like appearance of Peter, Lois, Chris, and Meg Griffin means their transition to live-action would be relatively easy. The only other Griffin that Family Guy would struggle to adapt is their talking dog Brian. Similar to adapting Stewie, Brian would be tough to re-create in the real world because it would be jarring to see a talking labrador walk on two feet, and although special effects could enable that a lot of Brian's personality would be lost from his animated form.
Outside the Griffins, Quagmire and Joe Swanson would be the trickiest regular Family Guy characters to transition to live-action because of their exaggeratedly large chins and jawlines, although arguably the pair are more defined by their actions so could do without their big heads. Jake Tucker, who is known for his upside-down head, would not suit a live-action remake, but given he is a fringe character he could easily be left off an adaptation. Unlike the main character Stewie Griffin who would have to be in a Family Guy live-action adaptation, his look and personality make that nearly impossible.