Despite his deep-rooted connection to the comic character, Simon Pegg wasn't cast as Hughie Campbell in The Boys - a decision that has subsequently proved wise. Since bursting into Hollywood with red on him in 2004, Simon Pegg has become known to a worldwide audience via Star Trek, Mission: Impossible, Hot Fuzz, and much more. As Pegg's star rose in the mid-late 2000s, Garth Ennis and Darick Robertson decided the British actor's likeness was perfect for a character in their new subversive superhero graphic novel, The Boys. "Wee Hughie" was the spitting image of Pegg, and the actor embraced his presence in the comic book world.
When Amazon came to assemble a live-action The Boys cast a decade or so later, Pegg was the obvious contender to play Hughie but, instead, he was chosen to play Hughie's father. Conventional wisdom dictates that the recently-turned-50 Pegg would've been too old to portray Hughie on TV, having inspired the comic character a whole 15 years prior, and the actor echoed these sentiments himself. In truth, Pegg's age wasn't that much of an obstacle. Hughie looks older in the comics, and Pegg could easily convince as a late-30s/early-40s protagonist. Ultimately, of course, the honor of getting covered in blood on a weekly basis went to Jack Quaid.
With two successful seasons in the bag, The Boys has justified denying Pegg the role he was drawn to play. Rather than the actor's age, the on-the-nose-ness of Simon Pegg's casting would've caused problems. For comic fans, seeing a live-action Hughie all but identical to the character drawn by Darick Robertson could've quickly become distracting. Sometimes, "obvious" castings just feel right (Maya Hawke in a Kill Bill sequel, for example), but hiring Pegg simply because comic Hughie was sketched in his image feels like casting in reverse. Of more concern is how Pegg playing Hughie would've severely limited the character's growth. Each and every main character in The Boys demonstrates more characterization and growth than their comic counterparts, but had Simon Pegg been cast as Hughie, audiences could'd never seen him as anything another than a carbon copy of the original.
With Jack Quaid, Hughie stands distinctly apart from the red-faced Scottish conspiracy theorist from the comic books. It's an entirely fresh take, free from the preconceptions Pegg would've inevitably bought, but Quaid's Hughie also greases the wheels for a stronger dynamic with Karl Urban's Billy Butcher. In both the comic books and the TV series, The Boys explains Butcher's attachment to Hughie as the result of his younger brother's death. Hanging around Hughie, Butcher can't help but be reminded of Lenny, and this tragedy underpins their relationship as mentor and somewhat-reluctant-student. Despite the age gap being narrower in the comics, the bond still works. On TV, however, fostering that "protective older sibling" vibe would've been far harder with Simon Pegg a few years Karl Urban's senior. Quaid is far better suited to the naive, deer-in-headlights, strawberry shampoo Hughie on Amazon Prime.
Casting Simon Pegg as a traditional Wee Hughie in The Boys would've represented a great nod to the source material, but despite the actor's oft-demonstrated versatility, offers little reward beyond a fun Easter egg. By casting Pegg as Hughie's father (also called Hugh; neat touch), The Boys finds a way to honor the comic books and include an actor who was pivotal to the franchise's early development, while also allowing Hughie free reign to find his own hapless path through a live-action world of sick and twisted supes.