Robert Wemyss was born on 5 March 1865, the son of John Wemyss, Inland Revenue Officer and Phyllis Pate.
He served his articles with Duncan McNaughtan. After completing his apprenticeship he worked as assistant for McNaughtan, for Burnet Son & Campbell where he was principally employed on railway work, for William Leiper, and for other unidentified firms before. He spent his holidays travelling and sketching in England, Scotland and Ireland. He commenced independent practice in Glasgow in January 1896, and was admitted LRIBA on 24 June 1912, proposed by John Bennie Wilson and the Glasgow Institute of Architects, which he had joined in 1907.
At the time of his admittance to the RIBA he was working in offices at 103 Bath Street, Glasgow, and living at 7 Glenan Gardens, Helensburgh.
Wemyss later moved his practice to 58 West Princes Street, Helensburgh. He worked on many buildings and project within Helensburgh including the Row Parish Council Chambers and the Open Air swimming pool in 1929.
He died on 30 July 1955 in the Royal Infirmary, Glasgow.
This biography draws on information published by the Dictionary of Scottish Architects