When Stephen Douglas Showalter was born on 8 June 1863, in Independence, Warren, Indiana, United States, his father, Andrew Anderson Showalter, was 46 and his mother, Tamor Riley, was 42. He married Eva B. Harvey on 16 February 1884. They were the parents of at least 4 sons and 4 daughters. He lived in Jefferson Township, Wayne, Indiana, United States in 1920 and Indianapolis, Marion, Indiana, United States in 1930. He died on 9 August 1934, at the age of 71, and was buried in Middletown, Henry, Indiana, United States.