Born and raised in Cardiff, Derek was educated in Cardiff at Cathays High School before undertaking a Mathematics Honours Degree at Bristol University.
He joined Price Waterhouse in Cardiff in 1975 immediately after graduating. He remained with the firm, which subsequently became PwC, until 2013, having been admitted to partnership in 1988, working at different times in Wales, the West Country and London. Since retiring from the partnership, he has continued to perform some consultancy work for PwC. Currently also a non-executive director of the Principality Building Society, Derek is also treasurer of St John Cymru Wales.
His other interests include playing golf, watching rugby, theatre and the arts.