 Loftus was the second son of Captain Henry Loftus, by his wife Diana, daughter of William Bullock of Sturston Hall in Norfolk.When Loftus was eighteen, his father purchased a commission for him in Ireland in the 17th Regiment of (Light) Dragoons, which was deployed to North America in 1775, where he saw action in the American War of Independence before returning to Ireland almost three years later.Loftus was promoted to major-general in 1796, lieutenant-general in 1803 and full general in 1813.