Born on 7 September 1808 in Glencree, Ireland,[1] Henry was the third son of Lieutenant colonel William Hart who served in both the Royal Navy and British Army before emigrating to the Cape of Good Hope in 1819 where he died in 1848.

[4] During the remainder of 1840 to the end of 1842, the regiment took part in the First Opium War where they were engaged in the battles of Canton, Amoy, Chusan, Chinhai, Chapu and the Heights of Chinkiang.

In 1856, when in temporary command of the depot battalion at Templemore, he suppressed a mutiny of the North Tipperary militia, defending the town of Nenagh.

In February 1839, supported by his wife and with the approval of the military authorities, Hart published the first edition of his Quarterly Army List, which was well received.

[7] Hart was allowed access to the official records of officers' services, and in 1840 published his first Annual Army List, containing supplementary information in addition to the contents of the Quarterly.