His son, Theodore K. Gibbs (born in 1840), served in the Union Army during the American Civil War. He was commissioned a 2nd lieutenant in the 1st Artillery in October 1861 and was promoted to 1st lieutenant in February 1862. He received brevets (honorary promotions) to the ranks of captain and major for gallantry in action at the battles of Olustee, Florida and Cold Harbor, Virginia respectively. He was a companion of the Massachusetts Commandery of the Military Order of the Loyal Legion of the United States. He resigned from the Army in May 1870 and lived in New York City and Newport, Rhode Island until his death in 1909.