 In 1841, Fergusson was made major-general, and served as colonel of the 62nd Regiment of Foot (March 1850), of his old regiment the 43rd Foot (1850–1853); then made lieutenant-general, he commanded the troops at Malta, and in 1855 the governor and commander-in-chief at Gibraltar.He resigned from the post in 1859, retiring to Bath.He was promoted to full general on 21 February 1860.