Hensleigh graduated from the University of Massachusetts Amherst in 1981 with a degree in history. He attended the University of Virginia School of Law, earned his J.D. from Tulane University Law School, and was admitted to the Massachusetts Bar in 1985. Before transition into writing, he worked as an attorney for seven years.
At the age of 31, Hensleigh began writing scripts and screenplays. He had previously written a novel and a three-act stage play but did not go to film school.