John Henry Phillips was born in Talgarth, Glamorganshire, Wales in 1860 and was articled to R. G. Thomas in Menai Bridge, Wales in 1879. He then worked as an assistant to William Parslow in Liverpool from 1881 to 1883 and to Henry Shaw from 1883 to 1885. Phillips commenced independent practice in Cardiff, Wales in 1887. He was elected a Member of the Society of Architects (MSA) in 1887 and a Fellow of the Royal Institute of British Architects (FRIBA) in 1904. He was also a member of the South Wales Society of Architect and its President.
His address was given as St. John's Square, Cardiff, and Clive Chambers, Windsor Place, Cardiff in 1904; and Gwylfa. Caerphilly, Wales in 1914; and 7, Pembroke Terrace, Cardiff in 1914 and 1919. He died in 1921.
Caerphilly Isolation Hospital; schools for Eglwysilan School Board; Bedwas and Maesycwmmer School Board; Penarth School Board; Williams' Pantycelyn Memorial Chapel, Llandovery; business premises, Queen Street, Cardiff; chapels, residences, warehouses,
Directory of British Architects 1834-1914. Compiled by Antonia Brodie, et al. Volume 2: L-Z. London; New York: British Architectural Library, Royal Institute of British Architects/Continuum, 2001