Walter Harry Mylechreest was educated at Oundle, Queens' College, Cambridge, and St Thomas's Hospital, London, where he qualified with the Conjoint diploma in 1931. Two years later he graduated MB, BCh. After an appointment as casualty officer and house physician at St Thomas's he joined a medical partnership in Windermere, a year later moving to Ambleside, Westmorland, where he was in practice until his last illness.
During the second world war he joined the RAMC and saw service overseas, first as a medical officer in the Hampshire Regiment and later as a pathologist with 33 General Hospital in Iraq, Sicily, and Malta. After demobilisation he proceeded MD in 1945.
He worked as a General Practitioner in Ambleside Westmoreland and became chairman of the Westmorland Division of the British Medical Association in 1955-6.1