The son of Douglas Walters and Clara Pomello, Walters was of English and Italian descent and was brought up as a Roman Catholic. At the outbreak of the Second World War he was in Italy and was interned, but after the Armistice of 1943 he was released and served for eleven months with the Italian Resistance. He then returned to England and was educated at Downside School and St Catharine's College, Cambridge, where he read Modern Languages.
In the late 1950s, Walters was employed as personal assistant to the Conservative peer Lord Hailsham throughout his chairmanship of the Conservative Party. In 1960, he was appointed MBE for political services.
At the 1959 general election, Walters contested Blyth for the Conservatives, fighting the seat again the next year at a by-election after Alf Robens was promoted to the House of Lords. In October 1962 he was selected as his party's candidate for the safe seat of Westbury, which he represented as Member of Parliament (MP) for 28 years from 1964. During his early years in the Commons he worked closely with Shadow Foreign Secretary Sir Alec Douglas-Home, of whom he later wrote "I could not imagine a more considerate, fair, or civilised person to serve."
Following the Six-Day War of 1967, Walters visited Palestine with his parliamentary colleague Ian Gilmour, and in a joint statement they said "The Israeli attitude to the refugees becomes clearer when their return rather than their expulsion is considered. Most people in Britain probably believe that Israel has agreed to their return and that repatriation is now satisfactorily proceeding. Nothing could be further from the truth." This was an early signal of the willingness of Walters and Gilmour to work closely together to explain the Arab point of view to the Western world, and they became close allies.
Outside parliament, Walters served as Chairman of Middle East International, founded in 1971 with "a mission to provide authoritative and independent news and analysis on the Middle East." A sympathiser with Arab interests, from 1970 to 1982 he was Chairman of the Council for the Advancement of Arab-British Understanding and from 1978 to 1981 joint Chairman of the Euro-Arab Parliamentary Association. He was also a company director with interests in investment, advertising, public relations and travel.
When the Conservatives returned to government in 1979, Walters's well-known pro-Arabism cost him the chance of advancement as a Foreign Office minister, the area in which his hopes lay, as in the shape of Gilmour Margaret Thatcher was willing to appoint one pro-Arab colleague, but not two.
Walters was knighted in 1988 and retired from parliament in 1992, to be succeeded as member for Westbury by David Faber.
Walters has been married three times: firstly in 1955 to Vanora, a daughter of the surgeon Sir Archibald McIndoe (divorced 1969); secondly to Celia Sandys, daughter of the politician Duncan Sandys (divorced 1979); and thirdly, in 1981, to Bridgett Shearer (divorced 1992). By his first wife he has one son and one daughter, by his second wife one son and by his third wife one daughter and one son.
From 1965 to the 1990s he served as a Governor of the British Institute of Florence.