Elwin McDowell Blackstone was born on June 20, 1917 to Alva and Gladys Blackstone who lived in Philadelphia. Elwin was the youngest of two sons. His father was a professor of business at Drexel University.
The family moved to Wayne, PA in the 1930’s, where Elwin graduated from Radnor High school in 1939.
On May 15, 1941, Elwin enlisted in the Army. He trained at Camp Lee, Virginia. After training, he joined the 317th Infantry, 80th Division.
Elwin marred Mary Louise Glover in Petersburg, Virginia, on March 6, 1943. Less than a month after his marriage, Elwin set sail for Reykjavik Iceland on April 4, 1943, sailing for England aboard the USS Gemini