All that is known of his early life was determined fron his entry in Alumni Dublinenses(pub. 1935):
GILBURNE, John (GILBOURNE). siz; Mr. Egan, Charleville; May 27, 1755;aged 19; s. of James, Agricola; b. Co. Limerick. Sch. 1758. B.A. Vern. 1759.
This tells us that he was born in County Limerick and educated by Mr. Egan at Charleville, and was a sizar student, i.e. one who did not pay a fee, but was educated in return for performing tasks, usually menial, while at the University. He was 19 when he began his course at Trinity College, Dublin, in May 1755, and graduated with a B.A. in 1759. His father was James Gilbourne, a farmer. His mother is unknown.
The subject of his degree is not given and it is not known whether he continued his studies elsewhere. By 1773 he was practising and teaching in Dublin. Newspaper adverts show he was offering his services in both pharmacy and midwifery

John Gilborne is remembered for his poetry as much as his medical abilities. Probably his most famous work is "The Medical Review, a poem; being a panegyric on the Faculty of Dublin Physicians, Surgeons and Apothecaries, marching in Procession to the Temple of Fame." Published in Dublin in 1775, this work contains all that is known of many early Irish medical men. The volunteer-review (1778) The triumphant return, A poem; in Latin and English: humbly dedicated to His Excellency George Greenville Nugent temple, Marquis of Buckingham, lord lieutenant general, and general governor of Ireland. Dublin 1788 De Regis convalescentia On the king's recovery, an allegorical poëm: in Latin and English. Alluding to the arms, crests, supporters, and mottos of the nobility of Great Britain and Ireland. By John Gilborne, M.D Dublin 1789.

No marriage has been found, and his death has not yet been traced.