Lieutenant William Thomas Fitzsimons (April 18, 1889 – September 4, 1917) was an American physician and United States Army officer in World War I, and is considered the first American officer killed in the war. Fitzsimons was born in Burlington, Kansas on April 18, 1889 to J.I. and Catherine Fitzsimons. Fitzsimons graduated with a Doctor of Medicine degree from the in 1912 and was a member of the Beta Theta chapter of Nu Sigma Nu.
When the U.S. entered World War I, Fitzsimons was called into active duty. He volunteered for overseas duty and left Kansas City on June 14, 1917. In 1955, PFC Albert T. Beinar was commissioned to paint a portrait of Lt. Fitzsimons. His painting was unveiled by Mamie Eisenhower during the seven-week stay of Dwight Eisenhower's heart attack recovery.