His mother, Susan, is a social worker. Through his maternal grandmother, Ashton is a ninth cousin, once removed, of English actor
Sam Claflin (through shared "Claflin" ancestry). Also on his mother's side, Ashton is a descendant of businessman John Jacob Astor (who is Ashton's five times great-grandfather), colonial official Robert Livingston the Elder, New York mayor/governor Wilhelmus Beekman, and other prominent New Yorkers of the colonial era.