Leonard William Thornton White was born in Uppingham, Rutland, England on 16 June 1901 and from 1916 to 1920 was articled to John Bilson (1856-1943) in Hull. He then worked as an assistant to various practices in Hul before establishing his own practice in Hull in 1927. He had been elected an Associate of the Royal Institute of British Architects (ARIBA) in 1926 and that year was an Ashpitel Prizeman.
After designing a number of houses in Hull and nearby and at Hessle and Kirkella in Yorkshire in late 1927 he moved to London where he designed several houses in Hampstead, Putney, Chelsea and Gidea Park.
In 1927-28 he studied at the Bartlett School of Architecture, University College London, and was a Soane Medallist in 1928 and a Henry Jarvis Student in 1928 which enabled him to study in Rome for two years. Following his return to England in 1930 he took up a teaching post at the London Polytechnic School of Architecture, Surveying and Building. During the next seven years, in addition to teaching he continued his private practice. Commissions on which he worked included a sports pavilion at King's School in Canterbury, Kent; and a Hotel in Weybridge, Surrey. In 1933 he was appointed vice-principal of the Architectural Association in London, and in 1937 was elected a Fellow of the Royal Institute of British Architects (FRIBA).
In 1936 he was offered the chair of Architecture at the University of Cape Town. and the following year moved to South Africa to take up the position. He subsequently remained in South Africa for the rest of his life. During these years he designed a house for the sculptor Ivan Mitford-Barberton (1896-1976 in c.1939); a layout for Nairobi in Kenya in 1947; the Wool Board Building in Cape Town (c.1949); and the and the Centlivres Building in Cape Town (c.1952). He died in Cape Town on 25 October 1965