After the death of his father (1829) Sherman lived as a member of the family of Thomas Ewing. In 1850 he married Ewing's daughter Eleanor Boyle Ewing, well known for her many philanthropic activities. After graduating (1840) from West Point, he spent several years at various Southern garrisons, served in the Mexican War, and was later stationed at St. Louis and at New Orleans. Resigning from the army in 1853, he was a banker in San Francisco and New York (1853–57) and a lawyer in Leavenworth, Kans. (1858–59), before he became superintendent of the state military academy at Alexandria, La. (now Louisiana State Univ. at Baton Rouge).