Sir John Gaspard Le Marchant was born in 1803 in England.

He was a British army officer and colonial administrator. He was educated at High Wycombe Royal Grammar School and the Royal Military College, Sandhurst. In 1820, he entered the army as an ensign, and made a series of moves upward, all by purchase. He became one of the youngest officers ever to command a British regiment. He served in Spain and the Cape Colony. In 1838, he was knighted by Isabella II, Queen of Spain. In 1847, Le Marchant became the governor of Newfoundland. With no prior experience in colonial administration, he faced a difficult situation. Severe economic difficulties were compounded by potato blight and the impact of a hurricane the previous September. He was opposed to the idea of responsible government and condemned local merchants for amassing wealth in the Colony and then returning to England. An unpopular governor, he left Newfoundland in 1852, to become Lieutenant-Governor of Nova Scotia. In 1859, he became governor of Malta and in 1865, Le Marchant was appointed Commander-in-Chief of the Madras Army before he retired in 1868.

In 1839, he married Margaret Anne Taylor (1820–1903). He died on February 6, 1874, in London, England.