Born into a liberal aristocratic family (see Trevelyan baronets of Nettlecombe, 1662), Charles was the eldest son of Sir George Trevelyan Bt MP, and his wife Caroline, daughter of Robert Needham Philips MP.

Family legend traced their ancestry to Sir Trevillian, one of King Arthur's knights, who swam ashore on horseback when the legendary land of Lyonesse sank.

After Harrow and Trinity College, Cambridge, Charles Philips Trevelyan decided upon a political career.

[2] Trevelyan was elected Liberal Member of Parliament (MP) for Elland, Yorkshire, in a by-election in 1899.

He served under H. H. Asquith as Parliamentary Secretary to the Board of Education between 1908 and 1914, when, as an opponent of British entry into the First World War, he resigned from the government.