During an encounter with Benny Russell on the streets of Harlem in 1953, Mulkahey gave Russell a hard time about his nice suit and his drawing of Deep Space 9 before finally allowing him to go.
He was later encountered by Russell at a crime scene where Jimmy was found dead. When Russell attempted to push past the officers, Mulkahey and his partner Burt Ryan severely beat Russell. (DS9: "Far Beyond the Stars")
Mulkahey was played by actor Jeffrey Combs, who also portrayed Weyoun. Concerning the task of portraying Mulkahey, Combs stated, "At first, I wondered where I could find Weyoun in this guy, but then I realized that his status as a suppressing authority figure is the synthesis for Weyoun in Benny's mind. So I approached him as a completely different character." (Star Trek: Deep Space Nine Companion, p. 535)