Sault was born in Inverness, Scotland, to a high-class English family. He fought in the British military since 1748 and was wounded in the French and Indian War in 1754, and recieved an honorary discharge. However, he re-joined as a Major in 1761 and became a Colonel by 1770, and was placed in charge of a regiment of Line Infantry, the 413th Regiment of Foot. Sault's troops were stationed in Falmouth, Province of Maine, and later joined the 3rd Indian Cavalry as an army.
With the Revolutionary War occurring in April 1775, Sault was ordered to abandon Falmouth and head to Augusta to provide protection for General William Howe's troops there. However, at Cavern Hill, Josh Hinkley's militiamen mauled his main body of troops, shooting as the regulars deployed into shooting lines. Sault was hit square in teh chest by a musketball, and staggered for a second, before collapsing to the ground. He died of blood loss a minute later. The Battle of Cavern Hill was a rare reverse for the Redcoats during the Revolution.