Resident Alien is an American science fiction comedy-drama television series created by Chris Sheridan, based on the comic book by Peter Hogan and Steve Parkhouse, that aired for four seasons from January 2021 to August 2025 on Syfy. It stars Alan Tudyk in the title role as an extraterrestrial who crash-lands on Earth with the intent to destroy the planet but develops a moral dilemma. In July 2025, it was confirmed that the fourth season would be its last.
Premise After crash-landing on Earth in a small Colorado town, an extraterrestrial sent to wipe out humanity kills a vacationing physician and takes on his identity. He is asked to do an autopsy on the town's doctor, who has died in unknown circumstances, and eventually takes over for the doctor at the town's clinic. He wrestles with the moral dilemma of his secret mission, while also dealing with the mayor's young son, who can see his true alien appearance. He develops compassion for humanity and ends up defending them from other extraterrestrial threats.
Cast and characters Main Alan Tudyk as "Harry Vanderspeigle", the titular alien with an unpronounceable birth name who has crash-landed in Patience, Colorado, killed the real Dr. Harry Vanderspeigle, and assumed his identity. He has been sent to Earth to destroy the human race, believing that this would benefit the planet, but he begins to question the morality of his mission after involuntarily forming human emotions. He is fascinated by humans and has learned how to speak English, as well as how to masquerade as a medical examiner from watching reruns of Law & Order. Although he attempts to blend in with people, he consistently stands out because of his misunderstanding of social cues and awkward speech and behavior. As the series progresses, he learns more about human emotions, behavior, and interactions, often closing episodes with a narration about what he has learned. He possesses superhuman strength, durability, and agility as well as advanced intelligence, shapeshifting abilities, and the power to alter or remove human memories. In the second-season finale, Harry is implied to be millions of years old, as he recalls seeing live dinosaurs. Tudyk also portrays the real Dr. Harry Vanderspeigle (seasons 1–2), a corrupt doctor and assassin involved with a crime syndicate who killed the previous town doctor, Sam Hodges Stuntman Keith Arbuthnot portrayed the alien for the first season while in his true form: an androgynous humanoid Octopodiform-like being. For the second season onwards, Tudyk performed the alien scenes using a practical effects-created mask. David Bianchi portrays Goliath (recurring season 2), Harry's future self, who traveled back in time and claimed a new human form as his own to save humanity from destruction. Goliath's artwork was created by Joe Vaux, storyboard artist and animation director for the TV show Family Guy. Sara Tomko as Asta Twelvetrees, the assistant to the town doctor at the Patience health clinic and a member of the Ute Native nation. In high school, she had an abusive relationship with classmate Jimmy and placed their daughter Jay for adoption. She is the first person after Max to discover Harry's true identity. Brylee Smith (guest season 1) and Zara Bacic (guest season 2) portray young Asta in flashbacks Corey Reynolds as Sheriff Mike Thompson, the town's sheriff, who refers to himself by the nickname "Big Black". He masks his insecurities by trying to control every situation. His career as a police officer in Washington, D.C., ended as a result of the death of his partner, leading him to eventually move to Patience. He also looks after Cletus, his former partner's pet and the town's police dog. Alice Wetterlund as D'arcy Bloom, bartender at the town pub, a local mountaineering expert, and Asta's best friend. After a skiing accident at the Olympics, she returned to her hometown and now spends her days tending bar and making questionable life choices. She discovers Harry's true identity after learning that the real Harry killed Sam Hodges. Elle Rivas (guest seasons 2–3) and Olga Petsa (guest season 4) portray young D'arcy in flashbacks Levi Fiehler as Ben Hawthorne, the town's young mayor. While he is charming and people-pleasing, his wife Kate tends to dominate their relationship. He previously dated D'arcy in junior high and high school, although they still seem interested in each other. He is a hobbyist candlemaker, but his work goes unappreciated. Since childhood, he has been regularly abducted by Grey aliens. Lukas Goas (guest seasons 2, 4) and Jude Wylie (guest season 3) portray young Ben in flashbacks Judah Prehn as Max Hawthorne, Ben and Kate's son, the only resident of Patience who can see through Harry's human disguise. Max is also able to see the "green glow" that is emitted by Harry's alien technology. Harry at first repeatedly threatens to kill Max, then plots to get him to move away; eventually, they reach a truce but continue trading insults. Elizabeth Bowen as Deputy Olivia "Liv" Baker (seasons 2–4; recurring season 1), the town's only deputy, who works with Sheriff Mike. She is underappreciated and ignored by the sheriff, although he gradually learns to appreciate her over time. After she briefly quits the force, Sheriff Mike, with some help, comes to recognize her skills, and the two begin to work together more in harmony. She has been fascinated by the possibility of extraterrestrials existing since she was a child, when she witnessed what appeared to be a UFO. Jessica Halliburton (guest season 2) and Camme Clarke (guest season 4) portray young Liv in flashbacks Meredith Garretson as Kate Hawthorne (season 4; recurring seasons 1–3), Ben's wife and Max's mother, who works as a schoolteacher after giving up her job as a lawyer when moving to Patience. She notes she has environmental law degree from CU Boulder.
Recurring Ben Cotton as Jimmy (season 1; guest seasons 2, 4), Asta's abusive ex-husband and Jay's father Kaylayla Raine as Jay, Asta's teenage daughter who works part-time at the Patience health clinic Deborah Finkel as Abigail Hodges (seasons 1–2), the wife of Dr. Sam Hodges, the previous town doctor Gary Farmer as Dan Twelvetrees, Asta's adoptive father and a Vietnam veteran, who owns the town's diner, Joe's Diner, which he has named in honor of a friend and fellow soldier he lost in the war Mandell Maughan as Lisa Casper (seasons 1–2), a sociopathic government agent who works for General McCallister Alex Barima as Lieutenant David Logan (seasons 1–3; guest season 4), an officer in the U.S. Air Force. After piecing together clues about Harry's crash landing, McCallister recruits him to find the alien and partners him with Agent Casper. He ultimately succeeds McCallister as the co-leader of the government's alien program. Jenna Lamia as Judy Cooper, Asta and D'arcy's childhood friend who works at the local bowling alley. She is sexually adventurous and often trades barbs with D'arcy. Lilly Dean (guest season 2) and Gwenna Cooper (guest season 4) portray young Judy in flashbacks Sarah Podemski as Kayla, Asta's cousin who is a mother and a lawyer Acahkos Johnson (guest season 2) portrays young Kayla in flashbacks Diana Bang as Ellen Cho, a nurse at the Patience health clinic who is disrespectful to almost everyone she encounters Gracelyn Awad Rinke as Sahar Karimi, Max's adventurous classmate and close friend. She believes him regarding Harry's alien identity, and is the more mature and responsible of the two. Elvy Yost as Isabelle Vanderspeigle (season 1; guest season 3), the real Harry's estranged British wife and an artist who won her husband over at a New York City art exhibition. In the third season, Harry's son Bridget uses her physical appearance as a disguise. Linda Hamilton as General Eleanor McCallister (née Wright) (seasons 1–3; guest season 4), a high-ranking U.S. military officer who secretly works for an unknown organization dedicated to hunting extraterrestrials, having spent her life seeking proof that aliens exist Alix West Lefler (guest seasons 1–3) and Ava Anton (guest season 4) portray young Eleanor in flashbacks Michael Cassidy as Dr. Ethan Stone (season 1; guest seasons 2, 4), who temporarily replaces Harry as the town doctor. Cassidy also portrays another member of Harry's species who kills the real Dr. Stone and assumes his identity, becoming a permanent replacement for Harry after his departure. Nathan Fillion as the voice of 42 (season 2; guest season 1), an octopus stranded in a restaurant tank (and on its menu) who can communicate telepathically with Harry Alvin Sanders as Lewis Thompson (season 2; guest seasons 1, 4), Mike's elderly father who moved with him to Patience due to his worsening condition Trevor Carroll as John Baker (seasons 2, 4; guest seasons 1, 3), Liv's husband and an avalanche-control team member Terry O'Quinn as Peter Bach (seasons 2–4; guest season 1), an "alien experiencer" who hosts the popular podcast Alien Tracker. Like Max, he can also see Harry's true form. Dylan Sloane (guest seasons 1–2) portrays young Peter Bach in flashbacks Justin Rain as Elliot (season 2; guest season 3), a Native American archaeologist who starts an on-and-off relationship with D'arcy Paul Piaskowski as Robert Hutchins (seasons 2, 4; guest season 3), Peter Bach's son, who was abducted by the Greys from his pregnant mother's womb and raised by the aliens Enver Gjokaj as "Joseph Rainier" (seasons 2–3; guest season 4), a Grey alien-human hybrid working for the Greys, and later, with Harry for General McCallister Nicola Correia-Damude as Detective Lena Torres (seasons 2–4), a detective based in Jessup, the neighboring town to Patience, who becomes romantically interested in Mike Kesler Talbot (season 2) and Andrea Geones (seasons 3–4) as the voice of the "Humalien" / Bridget, the human-alien offspring of "Goliath", Harry's future self. He initially disguises himself as Bobby Smallwood, a boy who went missing decades prior. Talbot also portrays the real Bobby Smallwood (season 2) in flashbacks Edi Patterson as Heather (season 3; guest season 4), a Blue Avian alien from the Galactic Federation, who becomes romantically involved with Harry Clancy Brown as the voice of the Mantid alien (season 4; guest season 3), a dangerous alien fugitive who escapes from captivity and takes Harry's place in Patience Jewel Staite as Jules Gardner (season 4), an FBI agent who grew up in Patience and begins investigating a series of strange murders in the town
Guest Jan Bos as Dr. Sam Hodges (seasons 1–2), the former town doctor for Patience, who is replaced by Harry Michael Adamthwaite as Howard Wright, Eleanor McCallister's father, whose obsession to prove that aliens exist drove him insane. He only appears in flashbacks. Giorgio A. Tsoukalos as himself (seasons 1–2), a ufologist who hosts a panel on Ancient Aliens at a UFO convention David Lewis as Mitch Green (season 2), the mayor of Jessup Alex Borstein as Carlyn (season 2), a laser physicist and Kate's cousin, who gets romantically involved with Harry Tommy Pico as Drew (seasons 2–3), a member of Asta's extended family who lives in the city Grace Dove as Sunny (seasons 2, 4), a member of Asta's extended family who is heavily pregnant Lini Evans as Bethany Bloom (seasons 2–3), D'arcy's mother Barclay Hope as Gerald Bloom (seasons 2–3), D'arcy's father Taylor Blackwell as Liza Vanderspeigle (seasons 2–4), the estranged teenage daughter of the real Harry. In the third and fourth seasons, Harry's son Bridget uses her physical appearance as a disguise. Maxim Roy as Violinda Darvell (season 2), the owner and operator of a prestigious art gallery in New York who was romantically involved with the artist "Goliath" Robert Moloney as Tanner Corrington (season 2), a criminal associate of the real Harry James Gallanders as Jack Sennett (season 2), D'arcy's former skiing coach