Laffan, Sir Joseph de Courcy (1786–1848), physician, was born 8 May 1786 in Cashel, Co. Tipperary, the third son of Walter Laffan of Cashel and his wife Eleonora De Courcy. Initially educated for the catholic priesthood at Maynooth, he found that he had no vocation and then studied medicine at Edinburgh University, graduating MD (1808). Admitted licentiate of the College of Physicians of London in December 1808, he set up practice in Portman Square, London. In 1809 he volunteered to work as a physician to the troops returning from the disastrous Walcheren expedition, many of whom had contracted serious illnesses and fevers while on campaign. The skill and dedication he showed in treating these men helped secure his appointment as physician to the forces in 1811 and he served in Spain and Portugal until the end of the Peninsular War in 1814. Moving to Paris, he set up practice and soon established a reputation as a physician of great ability.
After some years he returned to Rochester in Kent and was appointed physician in ordinary to the duke of Kent, brother of George IV. As a reward for curing the duke of a serious illness, he was created a baronet (1828). He was later made a gentleman of the bedchamber to the lord lieutenant of Ireland (1829) and a knight of the Hanoverian Guelphic Order (1836). He was also involved in the foundation of a woman's cancer ward at the Middlesex Hospital and donated a large sum towards its establishment. Forced to retire by ill health, he moved to Otham in Kent. He died 7 July 1848 at Vichy, France. His remains were returned to Rochester and buried in St. Margaret's Church.
In 1815 he married Jemima (d. 1839), daughter of Paul Pilcher of Rochester and widow of Colonel Symes who had been the British envoy at Ava in Burma. They had no children and, on Laffan's death, his baronetcy became extinct. His eldest brother was Robert Laffan (1765–1833), catholic archbishop of Cashel (1823–33).