[2] Castle began making his first pottery in 1947 and took night classes with Robert Nettleton Field at Avondale College, Auckland.

[3] In the early 1960s, Castle had an architecturally designed house built in the bush of the Waitākere Ranges at 20 Tawini Road, Titirangi, with a kiln and rail system out the back, and a low basement which allowed pottery to be exhibited.

Castle built a new house in South Titirangi with a larger kiln and even more extensive railway to serve it in 1972–73, which is still operating.

[6] In the 1986 Queen's Birthday Honours, Castle was appointed a Commander of the Order of the British Empire, for services to pottery.

[8] Castle was appointed as a Distinguished Companion of the New Zealand Order of Merit in the 2004 New Year Honours, for services to pottery.

[12] Six years later, Lopdell House Gallery's Making the Molecules Dance won the Montana New Zealand Book Award for best illustrative non-fiction.