sukup was born in muskegon heights, michigan in 1917. his parents, john and anna sukup, spoke slovak and identified their homeland in the 1910 census as "hun slovakia." his mother emigrated to the united states in 1897 and his father in 1899. his father worked as a core maker in an iron foundry. sukup had a brother, john, who was seven years older and two sisters, anna and lilian.