Jack Walter Lambert was born at Forest Hill in 1917, the only child of Walter Henry Lambert, a marine surveyor, and Ethel Mary Mutton. He was educated at Tonbridge School, which he left in 1934 to become a journalist on the Electrician, before moving to the Newspaper World in 1937 and the Fruitgrower, Florist, and Market Gardener in 1938. In 1939 his Penguin Guide to Cornwall was published, and in the following year he married Catherine Margaret Read, daughter of Alfred Read, a gifted baritone from whose singing teacher Lambert himself took lessons. In June 1940, Lambert volunteered for the Royal Navy, where he served with distinction in the Atlantic, Arctic and North Sea, and was mentioned in dispatches in 1944. After the war, Lambert joined the Sunday Times where he became successively Assistant Literary Editor (1948-60), Literary and Arts Editor (1960-76) and Associate Editor until his retirement in 1981. He died on 3 August 1985, aged sixty-nine.

During his Arts editorship of the Sunday Times the paper was famous for the quality of its literary, theatrical and musical coverage, and employed such critics as Cyril Connolly, Harold Hobson and George Steiner. Lambert had a wide acquaintance in the world of the arts, and his correspondence reflects his many friendships and professional dealings with distinguished practitioners in the field. He also served on numerous committees, including the Royal Literary Fund, the Council of RADA, the British Theatre Association, the Arts Council, the Council of the Society of Authors and Opera 80. He was awarded the CBE in 1970 in recognition of his public service.

Lambert made many broadcasts on the Home Service of the BBC and latterly for Radio 3. (He was particularly well-known for the programmes the Critics and Critics' Forum.) He also wrote numerous articles and reviews, principally for the Sunday Times. None of these have been collected, although Lambert did publish three books after the war: The Bodley Head Saki (1963); Drama in Britain, 1964-73 (1974), and the posthumously published The Bodley Head, 1887-1987 (1987), which was completed by Michael Ratcliffe.