Cullen's mother Florence Cullen () was killed in a car accident on December 6, 1977 at the age of 60, when Charles was in his senior year of high school. Charles recalled his mother's death as being "devastating", and his being upset that the hospital would not return her body—instead having it cremated. The following year, Charles dropped out of high school and enlisted in the United States Navy, where he served aboard the submarine USS "Woodrow Wilson". Cullen successfully passed basic training and the rigorous psychological examinations required for submarine crews, who were expected to spend as long as two months at a time underwater in a cramped vessel.