Born to Sephardic Jews who trace their ancestry back to the expulsion from Spain and settled in Hebron, Castel revealed a penchant for art at the youthful age of six.
In this, he was inspired by the artistic talents of his father, whose superb calligraphy on Torah scrolls and ornamental embroidery on silk Torah coverings was renowned.
Castel entered the Bezalel School of Art at the age of 13. The young man''s talents were so pronounced that his teachers suggested that he would be sent to France for further studies, and Castel left for Paris in 1927, at the age of 18 and stayed there for ten years.
He returned to Israel with the break of the second World War, where he settled in Safed.