Marin was born in Tanzania, where her parents had met while working in the Peace Corps. The new family moved to Boston when she was four months old. Her mother was a judge of the Massachusetts Superior Court, while her father was a college dean and teacher. Marin has credited her "proper, respectful, New England upbringing" as a possible reason for her success as an actress. "I've always felt like the reason I became an actor is because I look for more high drama than what I had at home," she told the Boston Globe.Marin originally planned to be a ballerina but, after an ankle injury suffered at the age of 16, she subsequently decided to pursue a career in acting. She attended Brown University and then enrolled in New York University's Graduate Acting Program at the Tisch School of the Arts, from which she graduated in 1991. Marin's earliest professional roles came on the New York stage, where she appeared in productions of "The Tempest" and "Electra" and also met her future husband, theatrical director Randall Sommer. The couple moved to Hollywood together in 1992, where Marin soon found small roles in films like the Geena Davis romantic comedy "Angie" (1994) and the film adaptation of the popular stage play "I'm Not Rappaport" (1996) starring Walter Matthau and Ossie Davis as a pair of cantankerous elderly friends. Marin's first starring role came in the low-budget indie "Chocolate For Breakfast" (1998), although she also began appearing in smaller roles in high-profile films like the Sean Penn vehicle "I Am Sam" (2001). Marin's true breakthrough role came in the shape of Judy Brooks, the younger sister of lead character Lily (Sela Ward) in Edward Zwick and Marshall Herskowitz's romantic drama series "Once And Again" (ABC 1999-2002). Malin's sensitivity shone through in this fondly remembered series about the troubled courtship of a soon-to-be-divorced mother and a divorced father, complicated by the couple's respective children and relatives. Despite the delicate nature of the show's subject matter, "Once and Again" ran for two critically acclaimed seasons and Marin found herself in increased demand. She joined the cast of "Two and a Half Men" the following year, and her acid-tongued character Judith quickly became an essential ingredient for the show's phenomenal success. While working on that hit series, Marin continued her film career, appearing in Nicole Holofcener's critically-acclaimed indie "Friends With Money" (2006), found-footage horror film "Quarantine" (2008) and occult thriller "The Haunting of Molly Hartley" (2008). Her television work during this period included recurring roles on cult-favorite series including "The Sarah Silverman Program" (Comedy Central 2007-08) and "Don't Trust The B---- In Apartment 23" (ABC 2012-13). In 2013, she was cast in the undercover-detective drama "Deception."