After postings to Cyprus and Palestine, he took part in the Italian campaign and finished the war, aged 25, in the rank of acting lieutenant-colonel
At the end of 1945 his regiment was disbanded, and Keith was appointed OC Troops in Sicily and lived in a comfortable villa at Catania. He returned to England the following year, and after demobilisation joined the family stockbroking firm of Parr and Rae (subsequently Tilney & Co) in Liverpool.
Keith retired as senior partner in 1982. He also became a director of the Isle of Man Bank and the Isle of Man Steamship Company.
An enthusiastic gardener, Keith also loved hunting, fishing, shooting, sailing and skiing. He was a lifelong supporter, and for several years chairman, of the Cheshire Hunt.
Keith died in 2010 aged 90. He married twice, with a with a son and three daughters from his first marriage.