He entered the United States Military Academy and graduated number twenty-three of fifty-four in the class of 1890.

[1] His classmates there included Colden Ruggles, Fred W. Sladen, Frank M. Caldwell, Clint C. Hearn, Daniel W. Ketcham, Edgar Jadwin, Francis Marshall, Harry H. Bandholtz, Henry D. Todd Jr., William C. Davis, George G. Gatley, Herbert Deakyne and William J.

He served as Chief of Artillery, first Army, and received the Distinguished Service Medal and another Silver Star.

[1] He received the Army Distinguished Service Medal during World War I, with the medal's citation stating the following: The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Army Distinguished Service Medal to Major General William Sharp McNair, United States Army, for exceptionally meritorious and distinguished services to the Government of the United States, in a duty of great responsibility during World War I.

[3]He received the Silver Star Citation for gallantry in action during the Philippine Insurrection, 1899 to 1902.