Губернатор Бомбея с 1795, до того резидегнт в Бенаресе. В Беранесе успешно прекратил практику инфантицида. Уважительно тносился даже к самым мелким раждам.
Поставлен на должность Корнуоллисом но и с братьями Уэлсли был в неплохих отношениях.
Биографическая справка из Stephen, Leslie. Dictionary of National Biography 16. London: Smith, Elder & Co. 1888:
DUNCAN, JONATHAN, the elder (1756–1811), governor of Bombay, son of Alexander Duucan, was born at Wardhouse, Forfarshire, on 15 May 1756. He received a nomination to the East India Company's civil service, and reached Calcutta in 1772. After serving in various subordinate capacities, he was selected, because of his known uprightness, to fill the important office of resident and superintendent at Benares by Lord Cornwallis in 1788. This was the situation in which most scandals had been caused by the eager desire for gain of the company's servants; Duncan put down these scandals with a strict hand, and thus made himself very unpopular with his subordinates. Yet he also found time to look into matters of native administration, and was the first resident who devoted himself to putting down the practice of infanticide at Benares. When Lord Comwallis returned to England, he did not forget to praise Duncan to the court of directors, and entirely without solicitation from himself he was appointed to the important office of governor of Bombay in 1795. He held this post for sixteen years, the most important perhaps in the whole history of the English in India. The effects of his long government are still to be seen in the present composition and administration of the Bombay presidency, for this was the period in which the company's servants were engaged in making the company the paramount power in India. Duncan went on the principle of recognising any petty chieftain, who had a right to the smallest tribute from the smallest village, as a sovereign prince. This policy accounts for the innumerable small states, nearly six hundred in number, now ruled through the Kathiáwár, Mahi Kantha, and Rewá Kantha agencies, which forms the distinguishing feature of the Bombay presidency, as distinguished from the rest of India, where only important chieftains were recognised as sovereigns, and the smaller ones treated as only hereditary zemindars. Though recognising their sovereign rights, Duncan had no hesitation in regulating the local government of these little princelets, and exerted himself especially for the suppression of infanticide in Kathiáwár. While thus occupied in local affairs, Duncan did not forget to take his full share in the great wars by which Lord Wellesley broke the power of Tippoo Sultan and the Maráthás. He equipped and sent a powerful force under Major-general James Stuart, which marched upon Mysore from the Malabar coast, and assisted in the capture of Seringapatam in 1799; he supplied troops for Sir David Baird's expedition to Egypt in 1801; he warmly seconded Major-general Arthur Wellesley in his campaign against the Maráthás in 1803; and he directed the occupation and final pacification of Guzerat and Kathiáwár by Colonel Keating's expedition in 1807. He died at Bombay on 11 Aug. 1811, and is buried in St. Thomas's Church there, where a fine monument has been erected to him. His eldest son Jonathan is noticed below.