The son of an attorney, Sir James Marriott entered Trinity College Cambridge as a pensioner in 1746 (LL.B. 1752, LL.D. 1757, Fellow, 1756-64); at Trinity he was Master (1764-1803) and Vice-Chancellor (1767-68). Marriott was admitted to the College of Advocates (1757), was King's Advocate (1764-68), and Judge of the Admiralty Court (1778-98); he was knighted in 1778 and M.P. for Sudbury (1781-84, 1796-1802). A friend of Gray and Mason, Marriott published verse in Robert Dodsley's Collection of Poems.
Poems ... By a gentleman of Cambridge. 1753.
Two poems to the Duke of Newcastle, Chancellor of the University of Cambridge. 1755.
The case of the Dutch ships, considered. 2nd edition, 1759.
Poems, written chiefly at the University of Cambridge, together with a Latin oration upon the history and genius of the Roman and Canon laws. 1760.
Political considerations, etc. 1762.
The rights and privileges of both universities ... defended. 1769.
Plan of a code of laws for the Province of Quebec. 1774.
Memoire justificatif de la conduite de la Grande Bretagne. 1779.