Harry O'Neill (catcher)

Of the 500-plus major league players who served in the military in World War II, O'Neill and Elmer Gedeon were the only players killed, both at age 27. The two have become symbols of "baseball's sacrifice" in the war effort. As the National Baseball Hall of Fame and Museum proclaims: "Ballplayers, like every other American citizen, understand the importance of giving one's self for their country." In 1980, O'Neill was inducted into Gettysburg College's Hall of Athletic Honor for baseball, football and basketball.

Following his time with the Athletics, O'Neill played in 16 games with the minor league Harrisburg Senators and also played semi-pro basketball and football. After the outbreak of World War II, O'Neill enlisted in the United States Marine Corps in 1942, and rose to the rank of first lieutenant with the Weapons Company, 25th Marine Regiment, 4th Marine Division. In January 1944, he took part in the amphibious assault on Kwajalein. On June 16, 1944, the second day of the Battle of Saipan, he was wounded in the shoulder by shrapnel, then treated for weeks back in the US. He returned to active duty in July, in time to participate in the Battle of Tinian. He was killed by a sniper at Iwo Jima on March 6, 1945. Among his surviving family was his young wife, Ethel McKay O'Neill.

As the third-string catcher for the Athletics, O'Neill appeared in just one game, as a late-inning defensive replacement. In a lopsided road loss to the Detroit Tigers on July 23, 1939, O'Neill caught the bottom of the 8th inning, and did not have a plate appearance.

Harry Mink O'Neill (May 8, 1917 – March 6, 1945) was an American professional baseball player who appeared in one game for the Philadelphia Athletics in 1939, as a catcher. O'Neill and Elmer Gedeon were the only two Major League Baseball players killed during World War II.