It Happened at the World's Fair
Kurt Russell had an uncredited speaking role as a boy who Mike Edwards pays 25¢ to kick him, thus giving him a chance to visit Nurse Warren. Russell would go on to play Elvis in the made-for-television film Elvis, provide the voice for Elvis in Forrest Gump, and portray an Elvis impersonator in 3000 Miles to Graceland.
Vicky Tiu, later grew up to be the first lady of Hawaii when she married Governor Benjamin J. Cayetano.
The Seattle Center, including the Seattle Center Monorail and the Space Needle, serve as backdrops for several scenes in the film. Security officers pursue Presley and the girl through the fountains at what is now the Pacific Science Center. The hitchhiking scene with Elvis and Gary Lockwood was filmed near Camarillo, California. as were some of the flying scenes. The entire hitchhiking scene to the point where they are both picked up by Kam Tong and Vicky Tiu Cayetano in the truck is easily recognizable as 5th Street near Pleasant Valley Road on the South side of Camarillo.