Julian Trevelyan was educated at Bedales School and Trinity College, Cambridge. He moved to Paris to become an artist and worked at Atelier Dix-Sept. Julian Trevelyan married the painter Mary Fedden in 1951.
From 1950 to 1955, Trevelyan taught History of Art and etching at Chelsea School of Art. He was Head of the Etching Department at the Royal College of Art, where he was influential to many younger printmakers, including David Hockney RA and Norman Ackroyd RA. In July 1986, Trevelyan was awarded a senior fellowship at the Royal College of Art and in September 1987 he was appointed a Royal Academician.