[6] McCullough came West in 1866 with his mentor Edwin Forrest where he grew as an actor through practice before audiences in Sacramento and Virginia City.
The most celebrated roles of McCullough's career, King Lear, Virginius, and Richelieu were first performed before Virginia City audiences.
[7] In 1869, in partnership with Lawrence Barrett, McCullough built the California Theatre on Bush Street in San Francisco.
He was known for an intelligent, but not intellectual Hamlet and had an average Joe quality in performance which tied him to the West's working classes.
According to this version of events, McCullough was murdered backstage by a fellow actor, was buried by members of the acting company in a cellar beneath the stage, and is a resident ghost.