Inman was born on February 19, 1843 in Jefferson County, United States. He was the son of Shadrach W. and Jane Martin (Hamilton) Inman, and the brother of John Hamilton Inman. His father was a prosperous merchant and planter, while his mother seems to have been a woman of unusual strength of character. Young Inman's early life was spent upon his father's plantation.
Inman studied at Maryville College. In the autumn of 1860 he entered the sophomore class at Princeton, but left the following April. In 1886 he received the honorary degree of A. M. from Princeton.
After studies Inman joined the Confederate army, enlisting as a private in the 1th Tennessee Cavalry, ending as a lieutenant on staff duty.
After the close of the war he worked in Augusta, Georgia, for a year or more, and, in 1867, with his father, opened a cotton office in Atlanta, which was to be his home until his death. The father returned to Tennessee in 1870, but the business was continued as S. M. Inman & Company. In 1896 Inman retired from active direction of the business, but he continued to give some attention to various financial and industrial enterprises. He was one of the organizers and was also a director of the Southern Railway, the yards of which in Atlanta are named for him.
He was a director of the Equitable Life Assurance Society, of the Atlanta Constitution, and of several banks. He was a close friend and trusted adviser of President Samuel Spencer of the Southern Railway, and of Henry W. Grady, the gifted editor of the Constitution.
Earlier he had been financially interested in some of the enterprises of his brother, John Hamilton Inman, to whom his sound judgment had been valuable. While still engaged in active business, he found time to work for the welfare of his city and section. He was treasurer of the International Cotton Exposition held in Atlanta in 1881, and backed it when failure seemed certain. He also made possible the opening of the Cotton States and International Exposition at Atlanta in 1895.
He was prominent in the agitation which led to increased appropriations for public schools and the establishment of agricultural high schools. He is known to have given away more than a million dollars in his lifetime, and the total of his benefactions was probably much greater.
Inman died in 1915.
Samuel Martin Inman was one of the founers of S. M. Inman & Company, became one of the largest dealers in cotton in the world, with several branch offices in different parts of the S. He was influential in founding the Georgia School of Technology, to which he contributed largely in money and time, serving as president of the board of trustees; he gave liberally to Agnes Scott Institute (now Agnes Scott College) and through his example interested others. He made donations to Oglethorpe and Emory universities, and was a member of the committee to choose Rhodes scholars for Georgia. Inman is also commemorated in the name of the Samuel M. Inman Middle School in the Virginia-Highland neighborhood.
Samuel was for many years an elder in the First Presbyterian Church of Atlanta.
Inman was twice married: first, February 19, 1868, to Jennie Dick of Rome, Georgia, who died in 1890; and, second, December 12, 1892, to Mildred McPheeters, daughter of Alexander M. McPheeters of Raleigh, North Carolina, who, with three children of the first marriage, survived him.
