An academically gifted child, he passed the Eleven plus and attended Queen Elizabeth's Grammar School in Atherstone; he then won a place at King's College London where he obtained a BA (Hons.)
Two years later he was commissioned into the Royal Army Educational Corps where he trained troops; by the end of the war he held the rank of captain.
At the 1945 general election, Chetwynd fought Stockton-on-Tees as the Labour Party candidate against the rising Conservative minister Harold Macmillan; in one of the first results to be declared, he won with a majority of 8,664.
In March 1948 he signed an all party motion calling for a 'Council of Western Europe' to prepare the way for an organic federation of European states.
However, in late 1961 he was applied for and was offered the job of Director of the North East Development Council, giving him responsibility for selling the region to overseas investors.
Shortly after his appointment Chetwynd began to 'sell' the North East region by giving a press conference for American firms where he argued that France was too politically unstable and West Germany had a labour shortage.
Later that year, his annual report complained that the north east had received fewer government grants for industrial development than other regions.
The North East Development Council made several attempts to get a personal meeting with Harold Macmillan, then Prime Minister, in 1963.
He was replaced as Chairman of the Northern Regional Health Authority in June 1982 by Norman Fowler shortly after criticising the Conservative government's conduct of a pay dispute, although this was said to have been a coincidence.