In 1964, after having been impressed with Mobley's performance as Gustav in Emil and the Detectives, Walt Disney signed him to the title role in the highly acclaimed and Emmy-nominated "Adventures of Gallegher" serials for his Wonderful World of Color. Gallegher is an amateur sleuth newspaper reporter, a character created by the author Richard Harding Davis. Contrary to popular rumor, it is Mobley's name that Walt Disney wrote on his very last memo.
some of his appearances on Disney's TV show include For the Love of Willadean, The Treasure of San Bosco, and the Mystery of Edward Sims.
After nine years and appearances in 118 television programs or feature films, Mobley's career was interrupted at the age of eighteen by military service. Mobley was quoted, accordingly: "Uncle Walt [Disney] had plans for me, but so did Uncle Sam, and Uncle Sam won." His last films with Disney were The Apple Dumpling Gang Rides Again and The kids Who Knew Too Much in the late 1970s and early 1980s.