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• Ken Jeong as Dr. Kendrick "Ken" Park.^[8] Ken is a constantly-joking, narcissistic, sometimes-thoughtless general practitioner employed at Welltopia Medical Group. He loves his family and coworkers but is often oblivious to their feelings. He has a younger sister, Dr. Wendi (Margaret Cho), of whom he is jealous.
• Suzy Nakamura as Dr. Allison Park (née Kuramata).^[8] Allison is Ken's intelligent Japanese-American wife and mother to Molly and Dave. She is a trained therapist/psychiatrist and often gives Ken advice about his life. Her children have a tendency to treat her with more respect than Ken. Allison usually tolerates Ken's antics, using them as an opportunity to push him to become a better man, although she occasionally becomes fed up with him.
• Tisha Campbell-Martin as Damona Watkins.^[8] Damona is the sassy and loud-mouthed office manager at Welltopia where Dr. Ken works. While she is technically under the jurisdiction of Dr. Park, she is seen as his equal in the office. She develops a sexual relationship with Pat, although she hates herself for it. It is revealed that she controls the schedules and vacation days for the office.
• Jonathan Slavin as Clark Leslie Beavers.^[8] Clark is a registered nurse who works with Ken and is usually his most devoted fan in the office. He is openly gay and prone to speaking in a loud volume when nervous or scared. He is a bit of a drama queen and can overreact to many situations. He is good friends with Damona and Dr. Julie Dobbs.
• Albert Tsai as Dave Park.^[8] Dave is Ken's son, age ten at the start of the series, who is considered "odd" among his peers and family. Though intelligent, he has a number of strange quirks, such as biting people when he feels cornered and conserving water to a drastic measure for the drought. When he is sad, he will eat food without utensils in bed. It is implied numerous times that he is not popular in school. Ken, Allison, and Molly often attempt to bribe him with pizza.
• Krista Marie Yu as Molly Park.^[8] Molly is Ken's daughter, age sixteen at the start of the series, and is a typical American teenager, obsessed with hanging out with friends, texting, and boys, though she is also very studious. She has several love interests throughout the series and has a habit of disobeying her parents. While she often tries to deceive her parents and brother, she does show some affection toward her family.
• Kate Simses as Dr. Julie Dobbs^[9] (season 1). Julie is Ken's protege and a trained doctor, although she is unsure of herself. She speaks in a nervous, high-pitched voice and is referred to as "fragile" by both herself and coworkers. She has a tendency to keep on talking when she's nervous, divulging Ken's secrets. She is an extremely thorough worker, to the point of spending three hours with a patient. On the season 2 premiere, it was revealed that she left the hospital to do a medical internship elsewhere.
• Dave Foley as Pat Hein.^[8] Ken's boss and the manager at Welltopia, Pat is an insensitive and slightly racist man who often is the butt of the joke. Although he considers himself a benevolent dictator among his coworkers, he's shown to be duped on several occasions since Ken, Damona and Clark are well aware that Pat frequently has ulterior motives. After separating from his wife, he lives on a boat parked outside her house. He fancies himself as a ladies' man, although he only succeeds in sleeping with Damona.
• Dana Lee as D.K. Park, Ken's stern, traditional father (season 2, recurring season 1). In the season 2 premiere, he starts to live in the Park household, saying his wife In-Sook (Ken's mother) left to visit family in Korea for a year. D.K. later confesses he and In-Sook are divorced. As he started living with his son's family, he gets more flexible in adapting to American cultures, such as being in a relationship with an American woman his age, much to Ken's dismay.

Recurring

• Marques Ray as Juan-Julio, the parking garage attendant at Welltopia
• Alexis Rhee as In-Sook Park, Ken's mother and D.K.'s ex-wife
• Stephen Guarino as Connor, Clark's partner and later husband
• Jerry Minor as Eric, Damona's boyfriend after she moves on from Pat
• Justin Chon as Jae, Molly's boyfriend in Season 2
• Zooey Jeong as Emily, Dave's brief girlfriend in Season 2
• Gillian Vigman as Megan, Pat's brief girlfriend in Season 2

Guest stars

• Margaret Cho as Dr. Wendi Park, Ken's sister, a talk show host.^[10]
• Mehmet Oz as himself^[11]
• Will Yun Lee as Dr. Kevin O'Connell
• Joel McHale as Ross
• Danny Pudi as Topher
• Jim Rash as Devon Drake
• Stephen Tobolowsky as Joe
• Ian Chen as Henry
• Randall Park as Gary Chon
• George Wyner as Dicky Wexler
• Jeff Ross as Doug
• Gillian Jacobs as Erin
• Yvette Nicole Brown as Amy
• Rhys Darby as Charles Evans
• Jonathan Banks as Dr. Erwin
• Dan Harmon as himself^[12]
• Alison Brie as herself^[12]
• Nia Vardalos as Tiffany, Pat's ex-wife

Jeong previously starred alongside guests stars Joel McHale, Danny Pudi, Alison Brie, Gillian Jacobs, Yvette Nicole Brown, Jim Rash and Jonathan Banks on the television comedy series Community. In the episode "Ken's Big Audition", Ken auditions for a fictional version of the show, in which Brie, series creator Dan Harmon, and other Community cast members Erik Charles Nielsen, Danielle Kaplowitz, Richard Erdman and Luke Youngblood also appear.^[13]

Season 1 (2015–16)

Season 2 (2016–17)

Ratings