During the Battle of Lake George he commanded the artillery that defeated repeated French attacks. After the battle he planned and led the construction of Fort William Henry, becoming its first commandant. In 1757 he left the command to George Monro when the 35th Foot relieved the 44th. During the Battle of Carillon (also known as the 1758 Battle of Ticonderoga) he was wounded leading his 888-men strong regiment during the failed attacks to take the French fort. He was later in charge of the rebuilding of Fort Ticonderoga. Having been promoted to Major in the 44th in 1756, he became an Engineer in Ordinary in 1758 and Chief Engineer of the Army and Lieutenant-Colonel in his regiment in 1759.