Cooper Joseph Koch ( KOTCH; born July 16, 1996) is an American actor. He is best known for his portrayal of Erik Menendez in the biographical crime drama series Monsters: The Lyle and Erik Menendez Story (2024), for which he earned nominations for a Primetime Emmy Award and a Golden Globe Award. Koch previously starred in the slasher film They/Them (2022) and the body horror film Swallowed (2022), and is set to star in Luca Guadagnino's upcoming biographical comedy drama film Artificial.
Cooper Joseph Koch was born on July 16, 1996, in Woodland Hills, Los Angeles, to a family involved in the film industry. His father, Billy Koch, who is of Jewish Russian descent, is the founder and owner of the horse racing club Little Red Feather and previously worked as a production assistant in numerous films. His mother, Kathy Kaehler, is a celebrity personal trainer. He has a twin brother, Payton Koch, who is a film editor, and a younger brother, Walker, who is a musician. His grandfather is film producer Hawk Koch, and his great-grandfather was film producer and director Howard W. Koch, both of whom served as presidents of the Academy of Motion Picture Arts and Sciences. His paternal great-granduncle was Charles Pincus, a California dentist known for inventing the dental veneer in 1928. Koch's great-uncle is businessman and former Democratic politician Alan Blinken.
Koch began acting in local theater productions at the age of five. He later attended Calabasas High School, where he performed in various stage adaptations such as West Side Story and A Midsummer Night's Dream. He was also a member of the school's a cappella group and orchestra, where he played the viola, as well as the boys' volleyball varsity team. In May 2018, he earned a Bachelor of Fine Arts degree in acting from Pace University.
Koch made his on-screen debut with a background role in the 2007 film Fracture, which was produced by his grandfather, Hawk Koch. In 2010, he appeared in the music video for "Ordinary Girl" by Miley Cyrus (performing as her character, Hannah Montana). From 2017 to 2021, Koch primarily appeared in short films and stage productions. He had a guest role in the episode "Forty Candles" of the comedy series West 40s (2018), and he was cast in Hulu's series adaptation of Bret Easton Ellis's novel Less than Zero, although the pilot was not picked up. In 2019, he starred in the Off-off-Broadway play Head First, for which he won the award for Outstanding Lead Performance in a Play at the Fresh Fruit Festival. He later starred in the television film A New York Christmas Wedding (2020), playing Azrael Gabison, a guardian angel who shows a woman an alternate version of her life. He also appeared in two episodes of the crime drama series Power Book II: Ghost.
In 2022, Koch starred in Carter Smith's body horror film Swallowed, which earned the Grand Jury Prize at the 2022 NewFest. He portrayed Benjamin, an aspiring gay pornographic actor who is forced to smuggle mysterious drugs by swallowing them. That same year, he starred in the Blumhouse Productions slasher film They/Them, playing Stu, a closeted gay jock who attends an LGBTQ conversion therapy camp.
Koch first auditioned for the role of convicted murderer Erik Menendez in the NBC limited series Law & Order True Crime: The Menendez Murders and the Lifetime television film Menendez: Blood Brothers (both 2017). He later earned the part in Monsters: The Lyle and Erik Menendez Story (2024), the second season of Netflix's true crime anthology series Monster. His performance received critical acclaim, particularly in the fifth episode, "The Hurt Man", a 34-minute one-shot of Erik detailing the sexual abuse he suffered from his father. Critics highlighted his portrayal as one of the season's standout performances, and he received praise from Lyle and Erik Menendez. The role earned him nominations for the Primetime Emmy Award for Outstanding Lead Actor in a Limited or Anthology Series or Movie and the Golden Globe Award for Best Actor – Miniseries or Television Film.
In October 2024, Koch signed with United Talent Agency for representation. In July 2025, he was cast in an undisclosed role in Luca Guadagnino's upcoming biographical film Artificial, based on the brief dismissal of Sam Altman as CEO of OpenAI. On March 4, 2026, he starred in a presentation for a Broadway revival of the comedy play The Little Dog Laughed.
Koch has collaborated with various luxury brands such as Yves Saint Laurent, Tiffany & Co., Armani, Ralph Lauren, Montblanc, Tod's, and Schiaparelli. In June 2024, he fronted Gap's summer collection alongside Japanese actress Kiko Mizuhara. In November 2024, he starred in the short film Togetherness, as part of a campaign by fashion house Yves Saint Laurent. In May 2025, he fronted Calvin Klein's Summer Essentials/Pride Month campaign. In 2026, he starred in the short film Postcards from Italy, directed by Roman Coppola, as part of a campaign by Montblanc. Koch has also modeled for Skechers and Patagonia while signed with Wilhelmina Models.
Koch is gay; he came out during college and has spoken about experiencing difficulties with self-acceptance after being bullied during his youth. He has also said that early in his acting career he faced challenges obtaining roles due to his sexuality and his "gay voice". Since 2024, he has been in a relationship with filmmaker Stuart McClave.