Hilary Swank a fost descoperita de mica de producatorul Suzy Sachs, care a invatat-o actorie. La varsta de noua ani a jucat in prima sa piesa ca Mowgli in "The Jungle Book" apoi a aparut in mod repetat in piese de teatru. A trait cu parintii ei in Bellingham, pana la varsta de saisprezece ani. In 1990, Hilary s-a mutat cu mama sa la Los Angeles, unde s-a inscris in South Pasadena High School, si a inceput sa joace ca profesionista.

A aparut in Buffy the Vampire Slayer (1992) iar in The Next Karate Kid (1994) a facut senzatie. Din acel moment a fost foarte solicitata oferindu-i-se diverse roluri.
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A castigat Oscarul pentru rolul din Boys Don't Cry (1999). A jucat in cateva filme din categoria B pana cand a fost distribuita in drama regizata de Clint Eastwood Million Dollar Baby (2004). Cu rolul din Million Dollar Baby a castigat Globul de Aur si Premiul SAG, si un al doilea premiu Oscar. A mai aparut in: Freedom Writers (2006) (pre-production), The Reaping (2006) (in curs de filmare), The Black Dahlia (2006) (post-production), Million Dollar Baby(2004), Red Dust (2004), Iron Jawed Angels (2004), 11:14 (2003), The Core (2003), The Space Between (2002), Insomnia (2002), The Affair of the Necklace (2001), The Gift (2000), The Audition (2000), Boys Don't Cry (1999), Heartwood (1998), Beverly Hills, 90210 (1990), Quiet Days in Hollywood (1997), The Sleepwalker Killing (1997), Leaving L.A. (1997) TV Serie, Dying to Belong (1997), Sometimes They Come Back, Terror in the Family (1996), Kounterfeit (1996),Cries Unheard: The Donna Yaklich Story (1994), Camp Wilder(1992) TV Serie, Buffy the Vampire Slayer (1992), Evening Shade (1990), ABC TGIF (1990)