Tierney gained the attention of Dr. James Gregory, the distinguished author of the Conspectus medicinae theoreticae, whose eldest son he vaccinated.
In the summer of 1802 he settled as a physician at Brighton, where he contributed materially to the formation of a vaccine institution in that town — the first that was established outside London.
[1][2] At Brighton Tierney was presented by his patron the Earl of Berkeley to the Prince of Wales (the future King George IV), who soon afterwards appointed him physician to his household there.
He was created a baronet (Baron Tierney of Brighthelmstone) in October 1818, and in the medical arrangements consequent to the accession of George IV, was gazetted physician in ordinary to the king.
[2] He was continued in the same high office by King William IV, who in 1831 created him a knight commander of the Royal Guelphic Order of Hanover.