Cast and characters
Peter Gallagher as Sandy Cohen, an idealistic public defender who takes in Ryan Atwood in the pilot episode, much to the dismay of his wife, Kirsten. He is the husband of Kirsten, the father of Seth Cohen, and the legal guardian of Ryan. Although he lives in an upper-class community, his politics are left-leaning and open-minded, causing friction between himself and the community. Gallagher described the character as a "leftie Jewish guy from the Bronx." Sandy deals with many conflicts throughout the series, such as trying to gain acceptance from his father-in-law while being financially supported by his wife, and raising two teenagers in a (sometimes) corrupting environment.
Kelly Rowan as Kirsten Cohen, the former CFO of real estate company the Newport Group, Sandy's wife, and Seth's mother. Before she met Sandy, she dated and grew up with Jimmy Cooper, father of Marissa Cooper, with whom she remains friends. She has had trouble with alcohol, which was triggered by the failing deteriorating relationship between her and her father. Kirsten goes on to open a dating service with Julie, and become a mother of two at the end of the fourth season. The character's politics and lifestyle are conservative, a contrast to her husband. Rowan described the character as seemingly more "together" than herself during an interview.
Ben McKenzie as Ryan Atwood, a troubled teenager from Chino who is brought into the privileged community of Newport Beach, California, after his mother, Dawn Atwood, throws him out of their family home. Ryan is subsequently taken in by his public defender, Sandy Cohen. He forms fast bonds with the entire Cohen family, especially Sandy's son Seth, in addition to the girl next door, Marissa Cooper. Ryan slowly finds his place within the new, materialistic society, and makes of the most of his situation by not only completing high school, but also continuing on to university. Casting director Patrick Rush found the role of Ryan particularly hard to cast and only invited McKenzie to an audition after Fox had made them aware of the young actor after his unsuccessful audition for a UPN sitcom. Rush said, "When Benjamin [McKenzie] came in, he wasn't physically what Josh had envisioned, but he inhabited the character unlike anyone we had seen. I think that the character of Ryan is a kid that always seems a little lost and has a sense of mystery and danger; Benjamin has all those qualities." Chad Michael Murray was originally offered the role of Ryan, but turned it down for the lead role of Lucas Scott on One Tree Hill.
Mischa Barton as Marissa Cooper (seasons 1–3), Summer's best friend and Ryan's on-and-off love interest. Marissa is portrayed as a "spoiled girl who adjusts to being poor." Throughout the series, Marissa battles addictions to drugs and alcohol, including nearly killing herself on a trip to Mexico with her friends. Marissa's relationships with her parents, boyfriends, and classmates are often tumultuous. The casting director referred to Marissa as "a girl stuck in the trappings of her life who seemed older than her actual age." Barton left the series at the end of season three when her character was killed in a car accident. Commenting on her departure, Barton said, "My character has been through so, so much and there's really nothing more left for her to do."
Adam Brody as Seth Cohen, the awkward adolescent son of Sandy and Kirsten Cohen. He is known for his quick quips, comic book fascination, and pop-culture references. Seth is also the love interest of Summer Roberts, on whom he had a crush since the third grade. Seth has been called a "Jewish nerd into obscure emo bands", who "starts dating a gorgeous, popular virgin." The New York Times characterized Seth as "eccentric and literate, Seth professes actual wanderlust [...] The show's press materials maintain that he's an existential hero along the lines of Holden Caulfield." Brody's portrayal of Seth was well received and is considered one of the overall highlights of the series.
Chris Carmack as Luke Ward (season 1; special guest star season 2), Marissa's first boyfriend and regular cast member for most of the first season. Luke is initially the main antagonist of the series, coining the series' famous "Welcome to the O.C., bitch!" line during a fight with Ryan in the premiere episode. However, he later becomes the main "comic punching bag" for the other characters. Schwartz characterized the later Luke as "strumming a guitar being a goofball." Luke leaves Newport Beach to live with his father in Portland at the end of the first season.
Tate Donovan as Jimmy Cooper (seasons 1–2; recurring season 3; special guest star season 4), Marissa and Kaitlin's father (and Julie's ex-husband). He gets in trouble for embezzlement and must face the consequences of his actions and its effect on his reputation and personal life. After his divorce from Julie, he pursues Hayley Nichol, Kirsten's younger sister, who eventually leaves him to further her fashion career in Japan. Jimmy's character made a brief appearance during season 3, but Jimmy was forced to leave town the morning of his wedding to Julie due to money problems. One interviewer characterized Jimmy as a "lovable deadbeat dad." Josh Schwartz has referred to the character as a "cat" in DVD commentaries. The character is portrayed as flighty and perpetually in financial debt despite warm relationships with his daughters. The character was ranked eighth on Entertainment Weekly's list of "TV's Worst Dads".
Melinda Clarke as Julie Cooper, the mother of Kaitlin Cooper and Marissa Cooper. At the beginning of the show she is married to financial planner Jimmy Cooper. She is often characterized as being devious, selfish, and shallow. However, she reveals a more vulnerable and empathetic part of herself a number of times during the series. Clarke summarized her character as being "clearly just such a money-digging whore. To me, it's so funny now to see The Real Housewives of Orange County because you realize it exists and that's what Julie was. Julie was obviously the original housewife." Clarke went on to commend the character's "incredible arc", saying that Julie started as "this woman who was so superficial but, of course, she's not just one-dimensional, she's multi-dimensional. Starting in her pink Juicy sweat suit outfit and then by the end she's graduated from college and moving on with her life. She's a survivor."
Rachel Bilson as Summer Roberts, a pretty and popular socialite who is the love interest of Seth and best friend to Marissa. Bilson's character was originally supposed to appear in only a few episodes, but quickly became popular amongst viewers, and ended up being part of the main cast for the rest of the series. When Summer's parents divorced, her mother abandoned the family and she has had no contact with her since. Her stepmother, nicknamed the "step-monster", is a lazy woman with a suggested drug problem. Summer has been referred to as a "seemingly snotty, superficial rich girl who is revealed to have hidden depth when she warms to the charms of nerdy Seth." She is the daughter of Dr. Neil Roberts. Summer later surprises audiences by turning out to be much more intellectually capable than imagined. She ends up being accepted to Brown, beating out many applicants from Harbour School, including, to his dismay, Seth. Not only intelligent, Summer proves to be an activist for animals while protesting against lab testing on animals and setting lab bunnies free. She later takes one as her own and names her Pancakes.
Alan Dale as Caleb Nichol (season 2; recurring season 1), Kirsten's businessman father and later Julie Cooper's husband. His character recurs throughout the first season, and he becomes a regular during the second season, but comes to a sudden stop when his character suffers from a fatal heart attack during the second-season finale. The Chicago Tribune characterized Caleb as a "gruff, uncompromising Newport Beach, California, real-estate developer". When asked by the Tribune about the character, Dale said, "The thing that's lovely about this character is that there's so much to do with him. His relationships are so complicated, and once the marriage happened, everyone was related in the show. That means he's got all these people to relate to, and he relates so badly with everyone."
Autumn Reeser as Taylor Townsend (season 4; recurring season 3), introduced in the third season as a neurotic perfectionist student. Many critics initially saw similarities between her and the character Tracy Flick from the 1999 film Election. Taylor begins the series as a villain before eventually becoming the second female lead in the fourth season. Reeser's performance was critically acclaimed. She reflected back on the character during a 2010 interview, saying, "I feel like there's a lot of girls out there who could really relate to her, who hadn't seen themselves on TV in that way. I loved that about her. I loved that she made no apologies for who she was even though she wasn't what all the magazines said was OK. She was like, "I'm still valid. And I'm awesome. And I know I'm odd, and that's OK."
Willa Holland as Kaitlin Cooper (season 4; recurring seasons 1 and 3). The role was originally played by Shailene Woodley in a recurring role during the first season. Kaitlin spends much of the series at boarding school before returning on a recurring basis in the third season (now played by Holland) and finally becoming a regular character in the fourth season. The daughter of Jimmy and Julie and sister to Marissa, her personality is more similar to her mother's rather than her father's, and she is portrayed as a regular pot smoker and occasional dealer. Holland observed that "no one can control her" but that her arc in the fourth season finds the character maturing. When asked about any disappointment over the recast, Woodley responded, "I was 11 and I was on as a guest, recurring character, or whatever. My character went to boarding school and when they decided to bring her back, they actually re-auditioned me to bring her back. But I didn't go through puberty until late [...] So, there was no weirdness when Willa Holland got it because she was so obviously right for the role... and I was so obviously not [laughs]."
