[2] Clendinning was born on 26 September 1924[3] in Richhill, County Armagh in Northern Ireland, the son of a furniture manufacturer.
He then studied at Belfast College of Art where his work included designing in the Baroque architecture style in the manner of Sir Christopher Wren.
[4] In 1944 he joined the Belfast architectural practice of Henry Lynch Robinson, which included working on Festival of Britain buildings in Northern Ireland.
[4] Clendinning is best known for his 1965 design of the "slot-together but sturdy looking" Maxima chair, inspired in part by computer lettering.
[5] He also created designs for Christian Dior and Liberty & Co.[2] His architectural work included Manchester Oxford Road railway station (1960), which has innovative laminated timber roofs.