Kirk is a classically trained actor and has the distinction of being "a true chameleon," with over 30 on-stage performances and more than 170 film & television credits, including star turns in the indie features The Best Christmas Pageant Ever (2024), Woodlawn (2015), Like Dandelion Dust (2009), Midnight Clear (2006), Hometown Legend (2002), Urban Justice (2007), The Lucky Ones (2008), and The Least of These (2008). His work in A.I. Artificial Intelligence (2001) lead to a substantial offer by the man himself, Steven Spielberg, in his film Minority Report (2002). His other studio films include Swordfish (2001) opposite Don Cheadle, Flightplan (2005) opposite Sean Bean and Jodie Foster, Wolfgang Petersen's Poseidon (2006), Clint Eastwood's Flags of Our Fathers (2006), and Resident Evil: Extinction (2007). On television he's played series regular and recurring characters on The Chosen (2017), The Event (2010), The Unit (2006), E-Ring (2005), Over There (2005), Charmed (1998). Strong Medicine (2000), The X-Files (1993), and NYPD Blue (1993). And has guest starred on such hit shows as NCIS (2003), Criminal Minds (2005), Bones (2005), CSI: Crime Scene Investigation (2000), Big Love (2006), 24 (2001), Rizzoli & Isles (2010), Switched at Birth (2011) and Extant (2014).