Fox had enlisted in the Civil War at Lyceum Hall on Dorchester's Meeting House Hill, which was the local recruiting office. He received his commission as Second Lieutenant in the Thirteenth Massachusetts Infantry; one year later he was made First Lieutenant. In 1863, he was transferred to the Second Massachusetts Cavalry, with the same rank. That same year he was made Major of the 55th Regiment, an African American regiment, being promoted to the rank of Lieutenant Colonel on November 3, 1863. The 55th Regiment had been trained at Camp Meigs, and was composed of African American men who had everything at stake in the war. Fox, with his fellow officers, were well trained, and were to be commended for their service. In Fox’s obituary, it was quoted as saying that “It was abundantly shown in his long and meritorious service in the army during the civil war, and especially in his readiness to enter a branch of the service that was not regarded with favor even by many who in theory favored perfect equality between races, and which was not calculated to attract the young soldier powerfully, in comparison with the more popular and agreeable positions in white regiments. But Colonel Fox believed in the equality of the black men with the white, and whatever he believed he lived up to, and the relations which existed between him and the colored soldiers in his command were ever the most intimate and mutually regardful nature.”
Fox was reared in the Unitarian faith, and upon the family’s removal in 1845 to Dorchester, they became connected with the First Parish Church on Meeting House Hill. The minister was the Reverend Nathaniel Hall, a fierce anti-slavery opponent who expounded upon the evils of both slavery and the subjugation of blacks in the South. His sermons, many of which were published for a more general readership, were vociferous and pointed in his belief that slavery was immoral, and could only be abolished through the war. Thomas B. Fox was undoubtedly influenced by Hall, and by his own father’s opinion, which was quite often read in the daily editions of the “Boston Transcript.”
Charles Barnard Fox served in the Army of the Potomac until after the Battle of Fredericksburg, in the Siege of Charleston and in the Campaign in Florida, the Battle of Honey Hill being particularly gruesome. His record of bravery and courage was made known when he was made brevet Colonel of the 55th Regiment; he resigned his commission on June 25, 1865 at the end of the Civil War and decided to remain in the South. For three years after the war, Fox managed a cotton plantation on Sea Island off the coast of South Carolina, it was not until 1868 that he returned to Boston, becoming an inspector at the Boston Customs House. In partnership with his brother and his friends, he assisted in the establishment of Holbrook & Fox, a real estate and land auction house in Boston. It was his friend Silas Pinckney Holbrook and his brother John Andrews Fox who created the partnership. The firm of Holbrook & Fox was one of the leading firms of its kind in New England and was well respected for the development of the real estate market in the late 19th century. Fox married and built a home, designed by his architect brother, on Fuller Street in Dorchester. His connection with the development of the old farms and estates of Dorchester continued until his untimely death in 1895.
The contributions of Colonel Charles Barnard Fox in regards to the Civil War were important enough to have his convictions and personal beliefs supersede his comfort. He served his all black 55th Regiment well, and earned their respect with the title of colonel by brevet, and honor that few officers received for their service in the Civil War.