Hartigan was elected President of the Royal College of Surgeons in Ireland for the year 1797.
In Cameron's History of RCSI, Hartigan is described as " having a good presence and agreeable manners, he secured a considerable amount of popularity in his circle.
"[2] Hartigan died on 15 December 1812, and was interred in St. Ann's Church, Dawson Street.
The house in which Hartigan so long resided (3 Kildare-street) was eventually sold to the Kildare Street Club, by whom it was pulled down.
There is a portrait of William Hartigan in the National Gallery of Art, Washington by US artist Gilbert Stuart.