Fuller was born on February 20, 1757 in North Stoneham, Hampshire. He was christened in the village of Waldron, near Heathfield in Sussex (now East Sussex). His parents were the Reverend Henry Fuller (January 15, 1713 - July 23, 1761) and his wife Frances, née Fuller (1725 - February 14, 1778). Fuller had two sisters: Elizabeth who married Sir John Palmer Acland and Frances who married Lancelot Brown, son of famed landscape gardener Capability Brown.
Jack Fuller lost his father in 1761, when he was four years old. At the age of ten, in 1767, he began his education at Eton.
On May 7, 1777, Jack Fuller's uncle Rose Fuller died leaving Jack his Sussex estates and Jamaican plantations. Jack Fuller thus took possession of the Rose Hill Estate (now Brightling Park) at Brightling at the age of 20.
Jack Fuller entered the political arena in 1780, at the age of 22, when he was first elected to Parliament. He was a Tory Member of Parliament for Southampton from 1780 to 1784, and for Sussex from 1801 to 1812. His cousin Hans Sloane was the other MP for Southampton at the same time.
There has been much speculation as to why Fuller never married. What is known is that in 1790, at the age of 33, he proposed marriage to Susannah Arabella Thrale,daughter of Streatham brewer Henry Thrale and diarist Hester Thrale, but was rebuffed. He is not known to have fathered any children.
In 1796, Jack Fuller was appointed High Sheriff of Sussex, for a period of one year, and in 1798, he became a captain in the Volunteer Sussex Yeomanry Cavalry. In the General Election of 1807, he was re-elected as MP for Sussex. However, on February 27, 1810, an incident with the Speaker in Parliament led to him being seized by the serjeant-at-arms and to public disgrace. Fuller retired from politics in 1812, not standing for re-election in the General Election of that year.
Fuller was a supporter and sponsor of the Royal Institution in London. He acted as mentor to the young Michael Faraday. In 1818 he loaned the Institution £1000 (about £100,000 in today's value) and later wrote off this debt. In 1828 he established the Fuller medal of the Royal Institution and in early 1833 he founded the Fullerian Professorship of Chemistry to which Michael Faraday was appointed as the first professor. Later he also endowed the institution with the Fullerian Professorship of Physiology.
In 1818, Fuller built the Observatory at Brightling which had been designed by Robert Smirke, and in 1822, he endowed Eastbourne in Sussex with its first lifeboat. In 1828, he financed the building of the Belle Tout lighthouse, on the cliff at Beachy Head, near Eastbourne. On Thursday, September 18, 1828, Jack Fuller bought Bodiam Castle, one of the most photographed British castles, for 3000 guineas at auction to save it from destruction.