Born in Hamilton, Ontario, Canada, she was the daughter of Croatian parents, and grew up in a multi-lingual household that left her fluent in numerous languages, including Bosnia, Serbian, Slovenian, French and Italian. During her teenage years, the family relocated to Illinois, where she graduated near the top of her class from West Aurora Senior High School in 1996. She returned to Canada to pursue her higher education in biology at the University of Toronto, but changed direction after receiving an offer to appear in a friend's independent feature. That film - a short titled "Acid Freaks" (1999) - served as the launching pad for her acting career.While Katic immersed herself in acting and theater training, she began landing parts in classical and modern stage productions. By 2003, she had made her feature debut in the shot-on-video thriller "Shut-Eye" (2003) and was logging appearances on a variety of TV series, including "Alias" (ABC, 2001-06) and "The Shield" (FX, 2002-08). In 2006, she enjoyed repeat engagements on "24" as Collette Stenger, an information broker for terrorists. The following year, she made two appearances on "Heroes" (NBC, 2006-10) as Hana Gitleman, a character introduced in the series' graphic novel spin-offs. Gitleman, who was able to receive and transmit electronic signals with her mind, played an integral role in two episodes of the show's first season before expiring at the hands of Greg Grunberg's Matt Parkman.The indie drama "Feast of Love" (2007) offered Katic the chance to play a character sans guns or nefarious plans; she was the "other woman" who comes between the marriage of lead Greg Kinnear and his wife Selma Blair, though it was the latter who runs to Katic after a particularly bad fight. After that project, she returned to playing tougher roles on "The Unit" (CBS) and the Canadian miniseries "Would Be Kings" (CTV, 2008). She was also top-billed in the violent independent thriller "Stiletto" (2008), starring as a trained Russian killer who eliminates an all-star cast of baddies - among them Tom Berenger, Tom Sizemore, William Forsythe and Michael Biehn - in spectacularly gruesome fashion.Katic continued on her action-oriented path with a cameo in the 22nd James Bond feature, "Quantum of Solace" (2008) as a Canadian spy targeted by the nefarious Quantum organization. Television soon beckoned with a juicy role as a saloon singer with psychic abilities in "Curse of the Judas Chalice" (2008), the third installment in TNT's popular "Librarian" series of TV movies. But she was back on the silver screen at the end of the year with Frank Miller's woeful adaptation of the cult comic series, "The Spirit" (2008), this time playing a rookie cop with sharpshooting skills.In 2009, Katic received the opportunity of a lifetime - the chance to topline a new television series - when she co-starred with Nathan Fillion on the series "Castle" (ABC, 2009-16). A comedy-drama in the vein of "Moonlighting" (ABC, 1985-89), the series followed a self-absorbed mystery novelist (Fillion) who reluctantly teamed with a no-nonsense homicide detective (Katic) to provide his expertise on solving crimes. The series performed modestly during its debut season, but soon found a devoted cult following that made it a steady ratings performer for the network. That following was outraged in the spring of 2016 when the show's network and producers announced that Katic's Detective Kate Beckett was being written out of the show at the end of its eighth season. The move, which came when Katic's contract was up for renewal, was reportedly due to budget constraints.