Grant played a pivotal role in the construction of several key railroads that made Atlanta a transportation hub in the southeastern United States. He was instrumental in designing and overseeing rail connections, which contributed to the city's rapid growth. During the American Civil War, he served as a Confederate officer. As an engineer, he supervised the construction of defensive fortifications around Atlanta, which became significant during the Atlanta Campaign of 1864.
Grant donated over 100 acres of land in southeast Atlanta, which became Grant Park, one of the city's largest and most beloved green spaces. The park is home to the Atlanta Zoo (now Zoo Atlanta) and the Cyclorama, a historic painting and exhibit.He was involved in various enterprises, including real estate, which furthered Atlanta's economic development after the war. Grant's contributions to the city, both in infrastructure and public spaces, left a lasting impact. His name lives on in Grant Park and in the recognition of his role in shaping Atlanta's early growth.