Harold Baker was born on 14 June 1890. It is not known where or with whom he trained as an architect. Between 1917 and 1928 he was in partnership with Thomas Falconer (1879-1934), first in Amberley, Gloucestershire and later in London. From 1922, when John A. Campbell (1878-1948) joined the practice, the firm was known as Falconer, Baker & Campbell.
Baker was elected a Licentiate of the Royal Institute of British Architects (LRIBA) in 1931. He was active as an architect in London until at least 1939.
Pfister, Rudolf. 'John A. Campbell in England in Gemeinschaft mit Thos. Falconer und Harold Baker. Baukunst vol. 6, June 1928 pp. 148-172
Wainwright, Shirley B. ' The work of Messrs. Falconer, Baker & Campbell'. The Studio 1925 pp. 25-27, 86-89