When William S. Harmon was born in May 1845, in Indiana, United States, his father, Mr. Lewis Harmon, was 40 and his mother, Mrs. Nancy Simpson, was 29. He married Amanda Ellen Wiley on 10 October 1867. They were the parents of at least 4 sons and 2 daughters. He lived in Montgomery Township, Gibson, Indiana, United States for about 10 years and Banner, Nebraska, United States in 1900. He died on 22 April 1922, in Portland, Multnomah, Oregon, United States, at the age of 76, and was buried in Multnomah Park Cemetery, Portland, Multnomah, Oregon, United States.