First married to Susanna Adams (daughter of John Adams and Sarah Stacy Gibbons) on 11 Sep 1783. She died ca. 1788. Thomas remarried to Frances Maitland Kennon (daughter of daughter of William Kennon and Unknown Female Gardner) in 1790 at Kentucky.
A veteran of the Revolutionary War, Thomas enlisted as a Private in 3rd Virginia Regiment, the same unit as his father, Colonel Thomas Marshall, Sr. He served through the remainder of the war, later being commissioned and achieving the rank of Captain.
Thomas Marshall, Jr. was the first Clerk of the County at Mason County, Kentucky. He is a younger brother of U.S. Supreme Court Chief Justice John Marshall.
Elizabeth Marshall Colston
Mary Ann Marshall Marshall
James Markham Marshall
Lucy Marshall Ambler
Alexander Keith Marshall
Charlotte Ashmore Marshall Duke