Meeker served in the Army from 1917 to 1919. He enlisted on July 7th, 1917 and was mobilized out of Brookings, SD on August 15th, 1917. He was transferred to Battalion E, 147th F.A., Camp Green, NC on November 8th, 1917. He sailed from New York Harbor on January 11th, 1918 and landed at Liverpool, England on January 17th, 1918. He trained at LaCourtine, France from February 20th til March 28th, 1918 and received further training at the Tractor School from April 4th to May 3rd, 1918. He transferred to Battalion E, 55 C.A.C. on May 4th, 1918. He was promoted to Wagoner on September 1st, 1918.

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He took part in the Second Battle of Marne, Operations on the Vesle (August 2nd-18th, 1918), and the Meuse-Argonne Offensive (September 26th-November 11th, 1918).

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After the end of the war, he sailed from Brest, France on January 10th, 1919 and landed at New York on January 22nd, 1919 at Camp Mills, Long Island. He then went to Fort Terry, NY on February 8th, 1919, and then to Camp Dodge, IA, where he was discharged on February 14th, 1919.