Cavenagh trained at
Addiscombe Military Seminary, the military academy of the
British East India Company. He passed his examination in June 1837, and in early 1838 joined the
32nd Regiment Native Infantry. In 1840, he passed the prescribed examination at
Fort William College,
Calcutta. He was appointed interpreter and quartermaster to the 41st Regiment Native Infantry. In 1840 and 1841, he was attached to the force employed in watching the
Nepalese frontier. He was adjutant of the 4th Irregular Cavalry (
Skinner's Horse), and in December 1843 was badly wounded in the
Battle of Maharajpore. His leg was severed just above the ankle by a round shot and his horse was killed under him. He was wounded again in January 1846 during the
first Anglo-Sikh war, when he was struck in the left arm by a ricochetting round shot. After this he was appointed as Superintendent of the
Mysore Princes and of the
ex-Ameers of
Sindh. In 1850, he travelled to Britain and France in political charge of the
Nepalese Embassy under
Jung Bahadur Rana. In 1854, he was appointed Town and Fort Major of
Calcutta. In this role he was responsible to the
governor-general,
the Marquess of Dalhousie followed by
Lord Canning, for the safety of
Fort William during the
Indian Rebellion. Lord Canning offered him the post of Governor of the Straits Settlements on 1 July 1859, In recognition of his services during the rebellion. He servered ties with Fort Williams on the 19 July and departed 28 July for Singapore on the
steamer Lancefield arriving on 7 August where he took up the post on 8 August 1859 relieving his predecessor
Edmund Augustus Blundell. Under a
royal charter of 1826,
Singapore,
Malacca,
Penang and
Dindings had been combined to form the
Straits Settlements. The Governor of the Settlements and his council were answerable to the
Governor-General of India in Calcutta. The Governor had little formal power, but was able to influence the Calcutta authorities who relied largely on the recommendations of these representatives on legislation and policy in each settlement. Control passed from Bengal to the
Colonial Office in London on 1 April 1867 and the Settlements became a
Crown colony. Cavenagh was the last Governor who reported to the Governor-General in Calcutta. His successor, Sir
Harry Ord, reported to the
Colonial Office in London. On 5 December 1866, he received unofficial word that he was to be removed from office on 1 April 1867 and resigned the commission himself on 15 March 1867. Cavenagh continued as a
general officer in the
Bengal Staff Corps, with promotion to lieutenant general in September 1874 and to
general in August 1877. ==Personal life==