Hidden in the psychedelic haze and pharmaceutical mayhem of “Common Side Effects” are a bunch of voice cameos that soar straight past you if you blink. And let’s be honest, if you’ve ever zoned out for even a second during this show, you probably missed at least one sneaky guest popping in (with plenty of “Wait, was that—?” moments). It’s not just your brain playing tricks; the creators—Joe Bennett and Steve Hely—know exactly how to keep the audience on their toes. They stacked the cast with comedians, beloved podcasters, and even some science brains to boot. If you like a side of “who was that just talking?” with your mushroom conspiracy, strap in.
Mike Judge: The Voice Behind the Boss
Let’s kick things off with an Adult Swim and animation legend. Mike Judge drops anchor as Rick Kruger, the smug, floundering CEO of Reutical Pharmaceuticals. From the first episode, Judge’s signature deadpan seeps into every one of Kruger’s lines.
You might recognize Judge’s vocal stylings from “King of the Hill” or “Beavis and Butt-Head,” because that’s his wheelhouse. The creators landed Judge, according to multiple interviews, because they wanted someone who could make “clueless corporate” not only funny but a little bit dangerous. He delivers lines like he’s chewing sleepy pills—which somehow makes everything twice as menacing. Watch the boardroom scenes (especially in Episode 2 and 3), and savor Judge’s understated bravado. There’s a sly wink in every word.
Martha Kelly: Dry Wit as DEA Agent Harrington
Sliding right into the next slot, we have Martha Kelly—yes, the one from “Baskets” and “Euphoria.” Kelly’s dry, almost anti-joke comedic delivery makes Agent Harrington one of those perfect middle-management bureaucrats. She’s a DEA agent, but don’t expect any high-speed chases. Her voice work leans into the exasperated, paperwork-choked kind of law enforcement.
Kelly shows up most memorably in Episodes 4 and 7, navigating office politics more than gunfights. The show’s creators told press that Kelly’s humor style fits their blend of awkward and absurd. If there’s a deadpan line about an interdepartmental memo, chances are, it’s Kelly.
Joseph Lee Anderson: Conspiracy Kingpin Energy
Let’s toss some youthful jitteriness into the mix. Joseph Lee Anderson, from “Young Rock,” shows up as Agent Copano—the guy who’s absolutely convinced that there’s a shadowy cabal behind every corn syrup packet. Anderson brings an undeniable energy, counterbalancing Kelly’s monotone with wild, manic theories.
You’ll find Anderson’s performances popping up from Episode 2 and onward. Each time Copano starts spinning a theory, the rest of the room checks out. But you won’t, especially if you catch Anderson’s feverish line delivery. According to the creators themselves, Anderson’s previous comedic work made him irresistible for the role.
Ben Feldman: VR Headset, Real Laughs
Now for a dose of the relatably clueless boyfriend. Ben Feldman, a sitcom darling from “Superstore,” becomes Nick—Frances’ significant other who might love VR almost as much as her. He doesn’t understand her obsession with fungi or the brewing conspiracy, but boy does he try (sort of).
Check out Episodes 1, 4, 5, and 6. Nick mostly hangs out at his desk, VR headset glued firmly in place, barely noticing the world crumbling around him. Feldman nails that “oblivious but lovable” vibe, so you get a laugh every time he zones in from virtual reality to drop a one-liner about dinner plans. He’s the comic relief after the comic relief.
Danny Huston: Big Pharma Just Got Scarier
Oh, you want some gravitas with your gummies? Enter Danny Huston—whose voice somehow always sounds dipped in oil and secrets. Huston gives us Jonas Backstein, fearsome Reutical board member and the closest thing to a proper Bond villain in the show.
Go to Episodes 3, 7, and the finale. Huston’s baritone comes waving a mix of charm and menace, which the showrunners say was exactly the tone they wanted. He doesn’t crack many jokes, but every utterance feels like a chess move. Listen up when boardroom politics take a dark turn.
Sydney Poitier: Political Chess, Animated
Moving to the murky world of show-business politics, Sydney Poitier plays Cecily, a politician wading through the corporate swamp that is Reutical. Her voice brings tension and longing—there’s always a sense she wants to do the right thing, but her phone keeps lighting up with bad news.
Watch for her turns in Episodes 2, 5, 8, and 10. Cecily represents every public figure squeezed between ambition and morality. The writers said Poitier’s ability to flex between hope and cynicism sold them. She does both.
Alan Resnick: Eccentric Sibling Vibes
No animated series is complete without a complete wild card. Enter Alan Resnick (“Unedited Footage of a Bear”), who breathes chaotic genius into Zane, Marshall’s off-the-wall half-brother. Resnick’s comedic sensibilities shine in Episode 4. Unlike the other cameos, he revels in surreal, rapid-fire lines that don’t always make sense—but always stick in your head.
His performance is the vocal equivalent of a sugar rush. The creative team wanted someone who could go really weird, really fast—that’s Resnick.
Shannon Woodward: Pharma Satire, Animated
Round the bend to Shannon Woodward, the versatile actor known from “Westworld.” Woodward gets the meta job of playing Amelia in the show’s internal pharmaceutical ads. She’s chirpy, slightly off-kilter, and perfectly mimics every PSA actress you’ve ever seen at 2 A.M.
Catch her in Episodes 1 and 4, playing up the contrast between “wholesome” ad-speak and the unhinged world outside the screen. According to the directors, she nailed the tone from the audition tape.
Andy Daly: Mysteriously Hilarious
Let’s not forget the drive-by comedy of Andy Daly (“Review,” “Eastbound & Down”). In Episode 3, he drops in as a Mysterious Passenger, never quite explaining his situation but chewing the scenery all the same. Daly darts in and out, almost like a fever dream, and manages to leave an indelible impression with about two lines.
Bob Stephenson: Steady Hand in the Storm
Jump to Episode 4 for Bob Stephenson (“Jericho”). He shows up as Connor, and for a moment, things look downright normal. Stephenson’s plainspoken delivery brings the show back to earth. Writers wanted someone to anchor that episode’s wild swings, and that strategy pays off. He brings a little gravity, but don’t worry, the weirdness wins out.
Timothy Simons: Legal Laughter
Things get delightfully weird in Episode 6, when Timothy Simons (“Veep”) arrives as the Lawyer. If you know Simons, you know what’s coming—blunt, biting, and oddly charming. He brings a whiff of political satire, poking fun at the intersection of law and pharmaceutical shenanigans.
Nicolas Cantu: The New Generation
Let’s not forget the next wave. Nicolas Cantu, teenage actor from “The Walking Dead: World Beyond,” voices Tommy in Episode 4. A younger perspective, some genuine energy, and just a hint of “what are the adults even doing?” Cantu keeps things fresh and fast-paced.
Why All These Sneaky Cameos?
So, what gives? Why did Bennett and Hely mine the worlds of stand-up, TV, podcasting, and even science for their supporting cast?
For one thing, it keeps the audience guessing. But more than that, each voice fits its character so well, you start believing these minor weirdos exist in real life. Interviews reveal the creatives wanted to blend the surreal with the sharply relatable. And grabbing comedians or actors with that unique spark means their voices burn into your memory—even if they’re only around for a few lines. Plus, these cameos bring a flexibility you don’t get with big-budget guest stars.
For example, having a science expert cameo as a lab tech in Episode 7 means a weirdly accurate one-liner about “Cordyceps genetic drift” instead of your usual TV gibberish. Or you get a Broadway-level punchline from someone who’s spent years delivering comedy on podcasts.
Moreover, the structure of “Common Side Effects” thrives on background chaos—so why not load the background with jokes, throwaway gold, and blink-and-you-miss-it moments from voices you maybe recognize?
Where to Catch Them—and What’s Next?
If you want to spot every cameo, sharpen your ears for:
- Drug-company board calls (listen for Judge and Huston)
- DEA briefings and water-cooler chatter (Kelly and Anderson own these)
- Commercial breaks nestled inside the show (catch Woodward and the hilarious parodies)
- Elevator and street scenes (blink and Daly’s gone)
- Family chaos (Resnick takes the crown)
Expect even more hidden gems when “Common Side Effects” returns for a (highly anticipated) second season. The creators have already hinted at weirder guest bookings, more podcasters, and even a revolving door of scientific experts. So keep your ears peeled—you never know if your favorite random voice might pop in to sell you migraine medicine or spark a viral meme.
Next time you’re rewatching Season One—because we know you’ll binge it again—turn up the volume, and try your hand at “Voice-Cameo Bingo.” You might just be the first to catch the next underground legend. Or at least, you’ll never listen to a throwaway line the same way again.
