David Eigenberg (born May 17, 1964) is an American actor. He is known for his roles as Steve Brady on the HBO series Sex and the City and as Lieutenant Christopher Herrmann on NBC's Chicago Fire. Eigenberg was born in Manhasset, New York, on Long Island, and grew up in Naperville, Illinois, the only boy in a family of six children. He has an older sister named Helen and a younger sister named Betsy. His mother, Beverly, owned pre-schools, and his father, Harry, was a certified public accountant. Eigenberg's father was Jewish and his mother was Episcopalian; he was raised in his mother's faith. After graduating from high school in 1982, Eigenberg enlisted in the United States Marine Corps Reserve, serving for three years (1982–1986), and was honorably discharged at the rank of Lance Corporal.