After amateur acting, Fowlds trained at RADA and made his debut on the West End stage in The Miracle Worker. He appeared in various film roles, including Tamahine (1963), East of Sudan (1964), Hotel Paradiso (1966), Frankenstein Created Woman (1967), The Smashing Bird I Used to Know (1969), Tower of Evil (1972) and Mistress Pamela (1974), prior to becoming familiar to British television viewers as 'Mr. Derek' in the children's series The Basil Brush Show, replacing Rodney Bewes as presenter. He played the role of Lord Randolph Churchill in the ATV series Edward the Seventh in 1975.
From 1983–85, Fowlds played the lead role in the sitcom Affairs of the Heart. He featured in a more sinister role in the 1990 political thriller Die Kinder. Fowlds then played Oscar Blaketon in the long running ITV police drama nostalgia series Heartbeat for its entire run. The character first appeared as the local police sergeant, then retired from the force and ran the post office before becoming a publican.
