Walter Krueger was born in Flatow, West Prussia, then part of the German Empire,[1] but now part of Poland.[2] He was the son of Julius Krüger, a Prussian landowner who had served as an officer in the Franco-Prussian War, and his wife, Anna, formerly Hasse. Following Julius's death, Anna and her three children emigrated to the United States to be near her uncle in St. Louis, Missouri. Walter was then eight years old.