English historian and statesman remembered for his biography of his uncle Lord Macaulay (Macaulay, Thomas Babington Macaulay, Baron) and for his part in the political events surrounding Prime Minister William Gladstone (Gladstone, William Ewart)'s introduction of Irish Home Rule (1886), which Trevelyan first opposed and then reluctantly supported.

Trevelyan was a Liberal member of Parliament from 1865 and served in various governmental capacities until 1897, when he retired from politics. His Life and Letters of Lord Macaulay, 2 vol. (1876), regarded as one of the best biographies in English, presents Lord Macaulay, a historian and Whig politician, in the round and, though sympathetic, is never partisan. His historical works include the Early History of Charles James Fox (1880) and six volumes on the American Revolution. Trevelyan succeeded his father in the baronetcy in 1886.