An early member of the London society and lay assistant to John Wesley, he was the son of the Rev. Dr. Henry Briggs of Holt, Norfolk. As early as 1744 he was a member of the Foundery society and was the leader of a band for single men. He became increasingly involved in the society's affairs. Probably through the Wesleys he came to know the Perronet family at Shoreham, Kent and in 1749 married Vincent Perronet's daughter Elizabeth. (She survived him over 30 years, dying at Walthamstow in 1822, still an active Methodist.) Their daughter, another Elizabeth (known as 'Betsy'), born on 7 February 1751, became the wife of the Rev. Peard Dickenson. Another daughter, Philothea ('Philly'), born c.1753, married Thomas Thompson of Hull.
Briggs and Wesley were temporarily estranged by the Grace Murray affair in 1749, but in 1751 he was named in Wesley's marriage agreement. In 1753 he was entrusted along with Thomas Butts with Wesley's publishing affairs, but relinquished that responsibility in 1759, probably because of the increasing duties of his appointment at the Ordnance Office in the Tower of London. He had died by 30 April 1788.