John F. R. Seitz was born on May 22, 1908, in Wilmington, Delaware, where he attended elementary school and high school. His parents were George Hilary Seitz and Margaret Jane Collins Seitz. He had five siblings.Thompson, William J. "John F. Seitz" in Assembly (West Point, NY) , September 1979. Retrieved July 26, 2016. A brother, Collins J. Seitz, was a judge of the United States Court of Appeals for the Third Circuit from 1966 until 1998.Thompson, Assembly, 1979, p. 137.
