He was an unsuccessful parliamentary candidate for the Brecon and Radnor constituency in 1950 and 1951, before being elected as Member of Parliament for Hereford in February 1956. He held this seat until September 1974, when he stood down. He held office as a Lord Commissioner of the Treasury from 1959 to 1961, as an opposition spokesman on communications and broadcasting from 1965 and as Minister of State at the Welsh Office from 1970 to 1974. He was appointed a Privy Counsellor in 1974.
Gibson-Watt later held public office as a Forestry Commissioner from 1976 to 1986, as Chairman of the Council on Tribunals, 1980–86, and as a Member of the Historic Buildings Council, Wales, 1975–79. He was also Chairman of Timber Growers United Kingdom, 1987–90 (Honorary President, 1993–98), a Fellow of the Royal Agricultural Society, and President of the Royal Welsh Agricultural Society, 1976 (chairman of the council, 1976–94).
In 1979 he was created a life peer as Baron Gibson-Watt, of the Wye in the District of Radnor.[3]
Gibson-Watt married Diana Hambro (born 1922), daughter of Sir Charles Hambro, in 1942, and their second son David Julian Gibson-Watt married Patricia Hewitt, a member of the Labour Party, who after their subsequent divorce was elected as an MP.
