For One Hundred and One Dalmatians (1961), Mattinson provided in-between animation; he also drew illustrations for the Little Golden Books adaptation for the film. After another lay-off, Mattinson, at the direction of Andy Engman, was reassigned to work as an assistant to Eric Larson. Under Larson's unit, he animated Ludwig von Drake for The Wonderful World of Color television series. This was soon followed with The Sword and the Stone (1963), Mary Poppins (1964), The Jungle Book (1967) and The Aristocats (1970).
