Thomas S. Martin was born on January 23, 1823, in Pennsylvania to John Martin. His father was an Irish immigrant. Martin probably grew up in Philadelphia, Pennsylvania, and by 1850, he was working as a book keeper. He married Elizabeth Barras on January 6, 1853, and they had four children: Maria, born July 2, 1855; John, born April 14, 1858; Richard, born May 10, 1859; and Effie, born on December 8, 1860. They lived in Philadelphia, and Martin worked as a wholesale druggist. On November 27, 1861, he received a commission as a lieutenant colonel in the 11th Pennsylvania Infantry. He was killed in the Second Battle of Bull Run on August 30, 1862.