[8][11] During the American Civil War, Mason joined the 2nd Regiment Mississippi Cavalry in either late 1860 or early 1861.

[13] On 5 June 1861, Mason transferred to the 6th Regiment of Brigadier General Thomas C. Hindman's brigade of Arkansas Volunteers.

[4][5][13] Following Johnston's removal from the command of the Army of Tennessee during the Atlanta Campaign, Mason joined the staff of John Bell Hood.

[5] Upon Hood's defeat at Nashville in December 1864, Mason joined Lieutenant General Richard Taylor's staff before rejoining Johnston in North Carolina at the end of the war.

[1][3][5][14] The couple had four children, with only one surviving to adulthood:[1][3] Following the war, Mason relocated to New Orleans, Louisiana where he became a merchant.