Fonnrereau was the eldest son of Claude Fonnereau, a wealthy Huguenot merchant who had settled in Ipswich. He succeeded his father in 1740, inheriting his estates, which included Christchurch Mansion in Ipswich.
Returned for Sudbury in 1741, he continued to sit for that constituency until 1768, several of those years in conjunction with Thomas Walpole, a business connection. However, he retained interests in Suffolk and was a member of the Free British Fishery Society, as well as MP for the constituency of Aldeburgh at the end of his life, serving briefly alongside his brother, Zachary Philip Fonnereau.
He died unmarried in 1779 and was succeeded by his brother, Dr. Claudius Fonnereau (1701-1785).
- Namier, L.B. (October 1927). "Brice Fisher, M. P.: A Mid-Eighteenth-Century Merchant and His Connexions". The English Historical Review. 42 (168): 514–532. doi:10.1093/ehr/XLII.CLXVIII.514. JSTOR 552412.
- Harris, Bob (February 1996). ""American Idols": Empire, War and the Middling Ranks in Mid-Eighteenth-Century Britain". Past and Present. 150 (150): 111–141. doi:10.1093/past/150.1.111. JSTOR 651239.
- "FONNEREAU, Thomas (1699-1779), of Ipswich, Suff. ". History of Parliament Online. Retrieved 3 December 2017.