So, you’ve binged Common Side Effects on Adult Swim. You’ve chuckled at the corporate satire, squinted at the trippy mushroom visuals, and maybe even Googled “are magic fungi actually like this?” But have you stopped to wonder who exactly is behind those gloriously bizarre voices? Who’s breathing life into this cast of Big Pharma weirdos, skeptical scientists, and conspiracy-chasing agents?
Well, buckle up. We’re diving headfirst into the cast list. And yes, it’s stacked. Not only with serious talent, but also with backstories that explain why these characters land so well. Let’s break it down.
Mike Judge Is Back (And More Meta Than Ever)
Let’s start with the legend: Mike Judge. You know him. You love him. Or you’ve at least muttered “uhhh… Beavis?” under your breath once or twice. He’s the guy who gave us Beavis and Butt-Head, King of the Hill, and Silicon Valley. Basically, he’s the Shakespeare of American workplace idiocy.
Now, in Common Side Effects, Judge voices Rick Kruger, the hilariously out-of-his-depth CEO of Reutical Pharmaceuticals. Picture a clueless executive flailing in a sea of lawsuits, secret research, and hallucinogenic fungi. That’s Kruger. And yes, it’s absolutely perfect.
What makes Judge’s performance so rich is the layering. He’s not just voicing another blowhard executive; he’s satirizing the exact type of guy he’s been lampooning for decades. Remember the soulless management drones in Office Space? Yeah, Kruger is their spiritual cousin, just juiced up with biotech buzzwords and sketchy ethics.
And don’t forget—Judge is also executive producing the series. So, his fingerprints are everywhere, not just in the vocal booth.
Emily Pendergast as Frances: Smart, Funny, and Deeply Over It
Emily Pendergast plays Frances Applewhite, the underpaid, overworked Reutical employee who finds herself knee-deep in scientific mayhem. You might recognize Pendergast from her scene-stealing moments on Veep, or her appearances in shows like Love and We’re Doing Good. But if you know her real roots, then you know why she fits this role so well.
She comes from The Groundlings—the legendary LA improv troupe that launched names like Kristen Wiig, Will Forte, and Melissa McCarthy. And Pendergast’s comedy chops shine here. She makes Frances charming, quick-witted, and just the right amount of frazzled.
More importantly, Pendergast gives Frances a subtle complexity. She’s not just “quirky sidekick material.” She’s the kind of protagonist you root for: smart enough to recognize the insanity around her, but human enough to still get caught in the mess.
Dave King: From the Writers’ Room to the Mic
Let’s talk about Marshall Cuso, the reluctant, shaggy, and surprisingly tender-hearted mycologist. Voiced by Dave King, Marshall is basically your lab partner who never stopped microdosing and somehow stumbled into a government conspiracy.
King isn’t just a voice actor—he’s a comedy writer’s comedy writer. He’s worked on Parks and Recreation, The Good Place, and even co-created English Teacher for FX. So, he understands comedic rhythm and structure like few others.
That background shows up in his delivery. Marshall could’ve easily been just another bumbling sidekick. Instead, thanks to King’s dry delivery and improv timing, he’s a lovable mess of skepticism and sincerity.
It also helps that King helped write Common Side Effects. When the actor knows the story beats inside out, the performance just hits different.
Martha Kelly Brings Deadpan Brilliance
Agent Hildy Harrington doesn’t blink. She doesn’t shout. And she definitely doesn’t suffer fools. But she does steal scenes. And that’s thanks to comedian Martha Kelly.
Kelly’s deadpan delivery has earned her a loyal fanbase—and serious acting cred. She was Emmy-nominated for her role in Euphoria and popped up in Spider-Man: Homecoming and Marriage Story. But comedy fans knew her way before that. Her stand-up is legendary for its subtlety and weirdness.
As Hildy, Kelly serves as the perfect counterbalance to the chaos swirling around her. She’s unflappable, sarcastic, and surprisingly grounded for someone tracking a supernatural mushroom. And every time she sighs or mutters a dry one-liner? It lands like a grenade.
Joseph Lee Anderson: Playing It Straight, With a Twist
Every good DEA agent needs a foil. Enter Agent Copano, played by Joseph Lee Anderson. He’s intense, a bit paranoid, and absolutely convinced that Something Big is going on. And let’s be honest—he’s probably right.
Anderson brings serious presence to the role. You might’ve caught him in Young Rock, MacGruber, or Divorce in the Black. He’s known for mixing earnest emotion with real physicality, and Copano lets him do both.
While other characters might be cracking jokes or chasing side quests, Copano is locked in. He’s the guy who never quite gets the joke but ends up driving the plot anyway. And Anderson plays that balance beautifully.
The Ensemble: Unsung Heroes Deserve Love Too
It’s not just the leads making noise (or, well, voice). The supporting cast here is rock-solid:
- Sue Rose, a veteran of animation, voices Hildy’s mentor. She adds warmth and texture.
- Ben Feldman shows up as Frances’ virtual-reality-obsessed boyfriend Nick. He’s both hilarious and weirdly sweet.
- Danny Huston plays Jonas Backstein, the shadowy board member with too much power and not enough scruples.
- Sydney Tamiia Poitier voices Cecily, a rising political figure entangled in the pharmaceutical madness.
Every actor contributes something memorable. Even the smallest roles feel specific, not throwaway.
Why the Cast Matters So Much
Let’s be real—animated shows live and die by their voices. The jokes might be on the page, and the art might be wild, but if the performances don’t hit? None of it works.
Common Side Effects works because its cast knows how to land a line, shade a moment, and let a pause speak volumes. They’re not just reading scripts—they’re living in these characters, quirks and all.
And the chemistry! You can tell these folks understand timing, both in comedy and storytelling. Whether it’s Pendergast snapping off a punchline, or Judge delivering some oblivious CEO mumbo-jumbo, the voices never feel static. They breathe. They bounce off each other. And they keep the show rolling forward.
So, Who’s Your Favorite Voice?
Here’s the fun part: everyone has their own MVP. Some fans swear by Judge’s boomer-fueled satire. Others stan Pendergast’s grounded chaos. Maybe you’re all-in on Agent Copano and his wall-of-red-string energy.
Whoever your pick is, the truth remains the same—Common Side Effects wouldn’t be half as fun without this wildly talented crew. So next time you hear Frances sigh, or Kruger blurt out something stupid, take a second to appreciate the craft behind the chaos.
Because in this trippy, satirical, and somehow weirdly heartfelt world? The voices are everything.
