After receiving some instruction at home, he was sent to Norwich grammar school, then under his father's close friend Samuel Parr.
About a year later he began to preach in the Temple Protestant de l'Oratoire du Louvre, and eventually obtained a grant from the consistory for the use of the church when it was not required for French service.
He was also an active supporter of the Royal Institution from its foundation, was appointed honorary librarian by the directors, and was engaged to deliver lectures there during three successive seasons.
Having been successful in this, he published some lesser works of less importance, while he was preparing for the press a new translation, from the French of Antoine Galland, of the Arabian Nights (1802), with twenty-four engravings from pictures by Robert Smirke, R.A. During the same year he brought out an edition of Anacreon, for which William Bulmer furnished a Greek font; the title-plates and vignettes were by Lavinia Forster.
An edition of Rasselas, with engravings by Abraham Raimbach from pictures painted by Smirke, was issued by Forster in 1805; it was followed in 1809 by a small privately printed volume of verse, entitled Occasional Amusements, which appeared without his name.
[1] Towards the end of 1790 Forster married Elizabeth, widow of Captain Addison, and youngest daughter of Philip Bedingfeld of Ditchingham Hall, Norfolk; his wife, by whom he had no children, lived only four years after their union.
On 3 August 1799, then resident at Weston, Oxfordshire, he married as his second wife Lavinia, only daughter of Thomas Banks, R.A., the sculptor.