Richard Caswell Hallmark was born on 29 March 1831 to Mynatt Hallmark and Polly Mary Calvert Hallmark. He married Mary E. Armstrong on 9 January 1854 in Blount County, Alabama. He is shown on the rolls of Company K, 19th Alabama Infantry Regiment, but it is unknown when he enlisted as he is not shown on the original muster roll when the company was formed in Huntsville in August 1861. He died while in service in Rome, Georgia on or about 1 November 1863.