When Harley Eugene "Si" Hylbak was born on 3 June 1917, in Lake Mills, Winnebago, Iowa, United States, his father, Elmer John Hylbak, was 22 and his mother, Evelyn Amanda Thoe, was 22. He married Lucille "Lou" Josie Thomsen on 12 August 1941, in Ames, Story, Iowa, United States. He lived in Spring Valley Township, Dallas, Iowa, United States in 1930 and Center Township, Winnebago, Iowa, United States in 1940. He died on 5 June 2009, in Richland, Benton, Washington, United States, at the age of 92, and was buried in Richland, Benton, Washington, United States.