On completion of his studies, Melendez was hired by Disney in 1935 where he worked on what are now considered classics: "Pinocchio", "Fantasia", "Dumbo", and "Bambi". Following the 1941 Disney strike, Melendez was hired by Leon Schlesinger Productions, later known as Warner Bros. Cartoons, where he served as animator on the "Looney Tunes" and "Merrie Melodies" series. He worked in Bob Clampett's unit until Clampett's departure, upon which he moved to the Arthur Davis unit. When the number of animation units at Warner Bros. was reduced from four to three in 1948, Melendez, moved to Robert McKimson's unit for a time.