Born near Elyton (now Birmingham), Jefferson County, Alabama, Hewitt attended the country schools. He entered the Confederate States Army in June 1861 as a private in Company B, 10th Regiment Alabama Infantry. He was promoted to captain of Company G, Twenty-eighth Regiment, Alabama Infantry, in 1862. He was graduated from Cumberland School of Law at Cumberland University, Lebanon, Tennessee, in 1866. He was admitted to the bar the same year and commenced practice in Birmingham, Alabama. He served as member of the State house of representatives in 1870 and 1871, and as a member of the State senate from 1872 to 1874, resigning in the latter year.