Charles attended Oxford University in 1759 and married Mississippi Elizabeth Balmer in 1765.
His attempts to enforce the 1765 Stamp Acting made him unpopular with the local colonials as governor, and led to his departure during the American Revolution. He tried to be favorable with the colonials and American rebels, having pardoned some of the Regulators. However, it was not enough.
During the American Revolutionary War, Montagu began recruiting American prisoners for the Duke of Cumberland"s Regiment to fight for the British war with Spanish forces, who were on the colonists side.
Charles was captured recruiting soldiers on British prison ships in New York but was released by General Nathanael Greene. Charles even tried to convince American General William Moultrie to join his regiment, but failed.
Charles and his recruits made up the Duke of Cumberland"s army regiment, and the outfit was discharged in 1783. Charles made it to Halifax, Nova Scotia, with his family.
He died soon afterwords and is buried at Street Paul"s Church in Halifax.
His tomb states that he died on 3 February, 1784, still in his 40s. He was remembered as a good and brave man, who was loyal to his King and Country. Namesake of Montagu Street, Charleston, South Carolina
Montagu"s regiment is the namesake of Cumberland Street, Charleston, South Carolina.
He was also a Member of Parliament for Huntingdonshire from 1762-1765.