He was one of two MLB players who paid the ultimate sacrifice during World War II (also Captain Elmer Gedeon of The United States Army Air Forces – KIA on April 20, 1944).
MORE: Athletes who died fighting for the United States | Hall of Famers who served in the armed forces
O’Neill was a three-sport star-athlete at Gettysburg College. He led the school’s baseball, football, and basketball teams to league championships. He made his Major League debut on July 23, 1939, for the Philadelphia Athletics, playing in just one inning without a chance at-bat in what would be his lone MLB appearance.
From the excellent SABR biography on O’Neill.
O’Neill sacrificed his baseball career for his country in its time of need at just 24 years of age, voluntarily enlisting in the United States Marine Corps in September of 1942.
First Lieutenant Harry O’Neill: Hall of Fame in my book.
Sporting News contributor Ryan Spaeder is the creator and owner/operator of the popular Twitter account Ace of MLB Stats (@aceballstats).
