William Smith (March 26, 1831 – January 17, 1912) was a career officer in the United States Army.

[1][5] In August 1861, Smith's application for a commission was approved, and he was appointed a paymaster in the Union Army.

[1] He was then transferred to the Department of the Northwest in Saint Paul, Minnesota, where he continued to serve as a paymaster.

[1][3] Smith was recommissioned as a major in the paymaster corps in January 1867, and continued to serve in Saint Paul.

[12] Smith served until March 25, 1895, when he left the military after reaching the mandatory retirement age of 64.

[3][15] As a result of his Civil War service, he was a member of the Military Order of the Loyal Legion of the United States.