William Fox lived at 2607 N. Waterloo Street in Philadelphia, PA with his mother Jennie Fox and his younger brother Charles Fox. He was born on June 7, 1909 and joined the military later than most youth at the time on December 10, 1943.

He entered the infantry in the medical department, so he most likely sought an education in that field before enlisting. William never wed before joining the war effort, making his beneficiaries his mother and brother.