Born in Edgefield, South Carolina, he later moved to Mississippi and represented Hinds County in the state legislature from 1859 to 1861. He was the only child of Henry Mims and Susan Burr Read of Edgefield, South Carolina.
During the United States Civil War, Major Mims served under General John C. Pemberton and saw action in the Battle of Jackson, Champion Hill and Vicksburg Campaign. He served on the staffs of John C. Pemberton and Joseph E. Johnston and shared friendship with Johnson along with continued business interests until Johnson's death in 1891.
After the war, he became southern manager of the New York Life Insurance Company (since 1868) and he was charter member and served 20 years as president of the Capital City Club. Following his death in 1906, he was buried in Westview Cemetery. In observance of his death, Atlanta's City Hall was closed for one half day, and free carriage rides were offered from City Hall to the Westview Cemetery.
Politically he was an old school Democrat and he was elected mayor of Atlanta in October 1900. The election came in the midst of Atlanta's streetcar war; he was supported by Joel Hurt (Atlanta Consolidated Street Railway Company) and opposed by Henry M. Atkinson (Georgia Electric Light Company).
Mims married Sue Harper, a native of Brandon, Mississippi, in 1866. Mrs. Mims developed a serious incurable illness that lasted 15 years until in early 1886 Sue Harper Mims was healed through Christian Science. She later became a Christian Science Practitioner and later a Teacher of Christian Science. Mrs. Mims also became a lecturer of Christian Science, traveling around the United States giving talks on Christian Science and Mary Baker Eddy, the Discover and Founder of Christian Science. She was instrumental in the development of Christian Science in Atlanta, Georgia, ultimately hosting church services in her home before the first Christian Science church in Atlanta was built. 
James G. Woodward
|Mayor of Atlanta
January 1901 – January 1903
Evan P. Howell