Robin Dunn was trained at Liverpool School of Architecture, University of Liverpool. In 1951-52 he assisted architect Gontran Iceton Goulden (1912-1986) in alterations made to the new premises of the Building Centre's in Store Street, London. In 1956 he was invited by Brice George and John Trew to become a partner in what became the George Trew Dunn Partnership.
Dunn retired in 1983. During his career he served on the panel of the Illuminating Engineering Society which produced the Lighting Guide of Hospital and Healthcare buildings from 1973-1977 and was a member of the Flint Committee on University building costs in 1976. After his retirement he was honoured by the University of Aberdeen by the conferment of an Honorary Doctorate of Law. He was elected a Fellow of the Royal Institute of British Architects (FRIBA).