Peter was encouraged by his mother to develop his artistic talent, especially painting and drawing. At the time (14 years old) he was working as a motor mechanic. It was around this time that Ellenshaw had a chance meeting with a local artist Percy "Pop" Day who would later mentor him not only in painting on canvas, but in painting on glass for the purpose of creating matte backgrounds for film.
This led to a brief yearlong stint at MGM, Ellenshaw worked at Walt Disney Studios on the film, "Treasure Island". As it turned out, his partnership with Disney would last over thirty years and earn him five Oscar nominations. However, after Walt Disney passed away in 1968 Ellenshaw became more engrossed with "his second career" - painting landscapes for the sheer beauty of it. The work of Peter Ellenshaw is represented in both public and private galleries worldwide.