Tierney, Sir Matthew John (1776–1845), physician, was born 24 November 1776 at Ballyscanlan, Co. Limerick, eldest son of John Tierney and his wife Mary, daughter of James Gleeson of Rathcannon, Co. Limerick. Educated at Mr Buckley's school at Athlacca, he then went to London where he studied medicine at Guy's and St Thomas's hospitals. On completing his initial medical training, he was appointed as surgeon to the South Gloucester militia, largely due to the influence of his friend the earl of Berkeley.
He became acquainted with Edward Jenner, a pioneer in the field of vaccination and also a friend of Berkeley, and soon became a firm advocate of vaccination, especially in relation to smallpox. Entering the University of Edinburgh in 1799, he convinced Professor James Gregory of its usefulness and Gregory later asked him to vaccinate his own son. In 1801 he moved to Glasgow University, where he graduated MD in April 1802. His doctoral dissertation was a study of the subject of cow-pock vaccination, entitled ‘Dissertatio de Variola Vaccina’.
After graduation he moved to Brighton, where he reestablished contact with his old friend the earl of Berkeley, through whose influence he was appointed physician to the prince of Wales's household. In September 1806 he became a licentiate of the College of Physicians in London and became physician extraordinary to the prince of Wales (1809) and physician in ordinary to him as prince regent (1816). He retained this position when the regent ascended to the throne as George IV (he later served as physician in ordinary to William IV). In 1820 he was called to attend George IV, who was suffering from a serious illness. Finding the king seemingly unconscious in his bedchamber, he had a whispered discussion with the other physicians present on the best action to take. Tierney insisted that the king had to be bled, but the other doctors objected. Eventually he offered to take full responsibility on himself for this course of action, and the others acquiesced. On recovering, the king, who had overheard the physicians’ discussion, remarked: ‘Well Tierney, you certainly have nerve’ (Gentleman's Magazine). Created a baronet in 1818, in 1821 he was elected an honorary fellow of the Royal College of Physicians of Ireland, and in May 1831 was created a knight commander of the Guelphic Order of Hanover. He published Observations on Variola vaccina or cow-pock in 1845.
In October 1808 he married Harriet Mary, daughter of Henry Jones of Bloomsbury Square, London. They had no children and, under the terms of a second patent of baronetcy issued in 1834, his brother Edward Tierney of Dublin, a crown solicitor for Ireland, succeeded him as baronet on his death. He died at Brighton on 28 October 1845. His death was deeply mourned by the people of Brighton as, extremely generous by nature, he had been an active figure in several of the town's charitable societies. He left an estate of some £30,000, and under the terms of his will bequeathed large sums to his two nieces, whom he wished to have the means to follow independent lives. He left £8,000 to Mary Tierney, daughter of his younger brother, Thomas Tierney, paymaster of the 43rd Regiment, and £5,000 to his other niece, Harriet Mary Tierney, daughter of Sir Edward Tierney. There is a small collection of his letters in the Royal College of Physicians in London.