He fought in the Battle of Belleau Wood, despite having a fever and being ordered to the back by his commanding officer, and took two Germans captive, earning the Distinguished Service Cross.

[1] In late June 1911, Miller requested and received his release from the Phillies so that he could join the Buffalo Bisons of the Class A Eastern League.

[5] After the 1911 season, the Phillies recalled Miller from Buffalo and traded him to the Sacramento Senators of the Class AA Pacific Coast League for Ben Hunt.

[12] He played for the Taunton Herrings until the team folded, and Miller finished the Colonial League season with the Springfield Tips.

[1] Following America's entry into World War I in April 1917, Miller enlisted in the United States Marine Corps as a private in June.

[19] He deployed to France with the 4th Marine Expeditionary Brigade in the 2nd Infantry Division, reaching the front lines in March 1918.

[20][21] Miller was hospitalized with a fever, but disobeyed his superior officer's command to stay in the rear so that he could participate in the Battle of Belleau Wood on June 6, 1918.

[24] He was hired as an umpire by the Class A Texas League for the 1920 season,[25] but he resigned over the summer because of the limitations from his leg injury.

[26] Miller returned to the Marines as a recruiter, and was promoted to sergeant,[27] but received another honorable discharge due to his war injuries in January 1922.

[1] In 1927, Miller married Margaret Icenhower, who worked in a beauty salon and had two children from a previous marriage.

[1] After the end of prohibition, Miller operated a tavern in St. Louis with Grover Cleveland Alexander, a former teammate with Philadelphia, as his partner.