Joseph entered the army and was assigned to Machine Gun Company 116th Infantry. He sailed for France with that unit aboard the USS Finland which departed Hoboken, New Jersey on 15 Jun 1918. The ship docked in the port of Saint Nazaire, France on 28 Jun 1918. The unit then went to trench warfare training and a period of acclimatization in a "quiet" sector on the front lines. A major offensive kicked off on 8 Oct 1918 in which the 29th Division took part. CPL Phillips took ill during the offensive and died of pneumonia on 11 Oct 1918.
CPL Phillips was repatriated and re-interred in Woodlawn Cemetery in Baltimore, Maryland near where Susan lived. Susan remarried. A cenotaph was erected in his memory at Hollies Baptist Church Cemetery at Keller, Virginia.