Common Side Effects' features some impressive starring performances from two actors who don’t usually get to take the spotlight. The Adult Swim/Max animated seriesCommon Side Effectsis an off-beat but cutting satire of modern medicine and government, wrapped up in a morally-driven conspiracy caper. After discovering a potential cure-all that could save countless lives across the world, fungi expert and general oddball Marshall Cuso finds himself on the run from the company and government who want to keep his knowledge a secret.
Bolstered by strong animation, an impressive voice cast, and heady concepts that go beyond the typical limits of modern animated shows,Common Side Effectshas been one of the best shows to debut so far in 2025. While the voice cast does include some legendary figures from animation, the central role of Marshall is played by someone more well known for their work behind the scenes than in front of the camera. Here isthe cast ofCommon Side Effects, who they play, and where you’ve seen their work before.
Born June 15, 2025
Active Since:2002
Actor: Marshall Cuso stars inCommon Side Effectsas Dave King, the central character of the animated series. Dave King has been working in television for years, but primarily behind the scenes as a writer and producer instead of an actor. Getting his start onCrank YankersandLast Call With Carson Daly,King went on to write for shows likeWorkaholics,The Simpsons,Parks and Recreation, andEnglish Teacher. He has appeared in many of those shows as a minor character.Common Side Effectsis his first voice-over role, as well as his first starring role in a show.
Parks and Recreation
English Teacher
“Field Trip,” “Convention”
Character:Marshall Cuso is the lead character ofCommon Side Effects, a well-meaning expert on fungai who finds himself on the run. After discovering a mysterious new strain of mushroom known as the Blue Angel that can heal any and all illness or injury, Marshall risks his life to bring the potential cure-all to his former high school friend Frances. Marshall isCommon Side Effects' main hero, even as the show shifts focus to other more morally compromised characters like Frances.
Born July 23, 2025
Active Since:2013
Actor:Emily Pendergast stars inCommon Side Effectas Frances Applewhite. Born in Youngstown, Ohio, Pendergast got her start in short films before making the move to television.Pendergast found her breakout role in season 7 ofVeep, where she plays Beth, the wife (and half-sister) of United States President Jonah Ryan. She has since appeared in several films likeDescendent, shows likeWe’re Doing Good, and podcasts likeMeet Cute.
LaRoy, Texas
Kayla
Character:Frances Applewhite is the secondary protagonist ofCommon Side Effects. A former friend and classmate of Marshall, Frances went down a different path and finds herself working as an executive assistant for Reutical Pharmaceuticals, which seeks to stamp out any knowledge about the Blue Angel before it reaches the public. While Marshall is the driving force ofCommon Side Effects,Frances' attempts to wrestle with her own ambitions and sense of morality is the show’s thematic core.
Born July 14, 2025
Active Since:1991
Actor:Mike Judge is one of the stars ofCommon Side Effects, as well as an executive producer on the show. Born in Guayaquil, Ecuador and raised in New Mexico, Judge’s short filmFrog Baseballintroduced the characters of Beavis and Butt-head, who were spun-off into a show for MTV.The breakout success ofBeavis and Butt-headled to the development of critically acclaimed shows likeKing of the Hilland films likeOffice Space. Judge voices characters in bothBeavis and Butt-headandKing of the Hill, and brings those talents toCommon Side Effectsas Rick Kruger.
King of the Hill
Idiocracy
Director, Writer, Producer, I.Q test machine
Character:Rick Kruger is a higher-up at Reutical Pharmaceuticals, as well as Frances' direct supervisor at the office. Initially presented as an aloof and careless executive at the company, the introduction of Blue Angel ends up causing a change in him. As the show progresses,Rick becomes a surprisingly reflective characterafter he learns the true potential of the mushroom — as well as the lengths Reutical will go to keep it hidden from the public.
Common Side Effects Supporting Cast & Characters
Common Side Effects Has A Supporting Cast Full Of Seasoned Character Actors
Common Side Effectshas a fairly large supporting cast of characterswho flesh out the setting and the personal lives of the characters with some impressive supporting players. Joseph Lee Anderson (Young Rock) and Martha Kelly (Baskets) play DEA Agents Copano and Harrington respectively, who find themselves investigating Marshall and becoming entangled in the conspiracy to keep Blue Angel secret. Frances' lazy boyfriend Nick is played by Ben Feldman (Superstore), while her dementia-afflicted mother Sonia is played by Lin Shaye (A Nightmare On Elm Street).
Common Side Effects Creators On What Makes Adult Swim’s New Conspiracy Thriller Unique [SCAD]
Common Side Effects is one of the most exciting shows coming out of Adult Swim in 2025, and the creators discuss the story with Screen Rant at SCAD.
Danny Huston (Yellowstone) serves as theCommon Side Effects' central overarching antagonist, Reutical board member Jonas Backstein, while Christine Ko (Dave) plays Kiki, a researcher at Reutical that provides favorable findings for the company.The most enigmatic character in the show is Hildy, Marshall’s former mentor who wants the Blue Angel for her own ends. Hildy is voiced by animation legend Sue Rose (Pepper Ann).Common Side Effectshas an impressive cast, serving as a great showcase for some talent that’s rarely taken center-stage in shows.
