When Oscar Henry Harwell Sr was born on 27 February 1885, in Putnam, Callahan, Texas, United States, his father, Lunsford Dillard Harwell, was 27 and his mother, Elizabeth Cathey Hutcheson, was 19. He married Etta Eva Fleming on 23 December 1917, in Taylor, Texas, United States. They were the parents of at least 1 son. He lived in Justice Precinct 8, Callahan, Texas, United States in 1910 and Abilene, Taylor, Texas, United States for about 10 years. He registered for military service in 1917. He died on 15 June 1954, in Phoenix, Maricopa, Arizona, United States, at the age of 69.