Kirk has worked primarily as a voice artist on a number of anime shows, including Cowboy Bebop, Ghost in the Shell: Stand Alone Complex, and .hack//. He got his start as a sound coordinator on the movie Killer Klowns from Outer Space (1988) before getting acting roles in television and film, including Salute Your Shorts (1991), 3 Ninjas: High Noon at Mega Mountain (1998), and a number of guest roles on shows such as Felicity, Sisters, and NYPD Blue (with Sharon Lawrence).