From the late 1960s, Kyle began an academic career, while remaining active as a journalist for some years. He was a Fellow of the John F Kennedy Institute of Politics at Harvard (1967–68) and joined Chatham House in 1972, where he remained for 30 years. In the late 1980s, St Antony's College, Oxford invited him to become an associate member. His history, Suez: Britain's End of Empire in the Middle East (Weidenfeld & Nicolson) first appeared in 1991, and is regarded as definitive in almost all the cited articles. His other books include The Politics of the Independence of Kenya in 1999 and his posthumous autobiography Keith Kyle: Reporting the World appeared in June 2009, published by I.B.Tauris.
Kyle had a chequered career as a parliamentary candidate. He had hoped to become a Conservative candidate in 1956, but government policy on Suez dissuaded him. He was an unsuccessful Labour Party candidate in St Albans in 1966, for Braintree in both 1974 elections and was the Northampton SouthSDP candidate in 1983.