A veteran of the siege of Louisbourg, and the leader of the ascent to the Plains of Abraham (Quebec, 1759), he was dispatched in 1775 as second in command to Gage. After directing the attack on Bunker Hill, he succeeded Gage as commander, and coordinated a strategic retreat from Boston to Halifax. In Halifax, he coordinated a joint army-navy attack with his brother, Richard, an admiral, resulting in a campaign which allowed the British to control New York City. After his attempts to secure a peace in 1777 failed, he led the attack on Philadelphia, defeating Washington at Brandywine. After this, he wintered in Philadelphia, waiting for acceptance of his resignation, due to the failed peace negotiations. On May 25, 1778, he relinquished command to Sir Henry Clinton and returned home.