William Ellis Crompton, Jr. was born July 31st, 1867, to William Crompton and Hannah Hobson-Crompton. He is the sixth of twelve children, and the first of the twelve to be born in the United States. While his oldest brothers and sisters were born in England, he was born in Wyoming, USA, where his parents had settled.

William married Mary/Maule (sp?) Parry, daughter of John Parry, and the two lived in Park City, Utah. Any number of children unknown.