Philip C. Walker studied at Trinity College, Dublin, where he qualified as Bachelor of Medicine (MB) and Bachelor of Surgery (BCh) in 1890, and as Doctor of Medicine (MD) in 1893. In 1900 he was furthermore awarded the Diploma in Public Health (DPH) of the Royal College of Physicians and Surgeons of Ireland. After qualifying he held the following positions: resident medical officer at the Liverpool Fever Hospital; resident medical officer at the City Hospital, Park Hill, Liverpool; medical officer of health for the Fermon electoral division, county Cavan, Ireland; medical officer at the Farney Baronial Fever Hospital, Carrickmacross, Ireland; assistant medical officer of health at Paisley, Scotland; and assistant physician at the Paisley Fever and Smallpox Hospitals. In November 1902 he came to South Africa to take up an appointment as district medical officer of health for the western Transvaal. In June 1905 he became inspecting medical officer of health of the Transvaal Colony, under Dr George Turner*. He held this position until early in 1908, when he succeeded Dr Turner as medical officer of health of the Transvaal Colony. The next year he was granted six months leave to go to England for surgical advice, and died there.
Walker was married to Mary Jones, who died in 1904.