A physician. The son of Robert Gamble Cabell and Margaret Sophia Caskie Cabell. His grandfather, William H. Cabell, was governor of Virginia from 1805 to 1808. Robert married Anne Harris Branch 14 Nov 1877 in Richmond. Their sons were Robert Gamble III, James Branch and John Lottier Cabell.
He fought as a VMI cadet at the Battle of Newmarket.