The motion picture was filmed in Seattle, Washington, site of the Century 21 Exposition, the 1962 World’s Fair. The governor of Washington at the time, Albert Rosellini, suggested the setting to Metro-Goldwyn-Mayer executives.
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 truck drives by the largest wooden trestle in the Pacific Northwest, the Wilburton Trestle, which is located in Bellevue.
Mike and Danny fly a cropduster, but because of Danny’s gambling debts, a local sheriff takes custody of it. Trying to earn money, they hitch-hike to the World’s Fair in Seattle. While Danny tries to earn money playing poker, Mike takes care of a small girl, Sue-Lin, whose uncle has disappeared. Being a ladies’ man, he also finds the time to court a young nurse, Diane.
It Happened at the World's Fair, a musical comedy filmed against the backdrop of the 1963 Seattle World’s Fair, Elvis Presley’s character, Mike Edwards, and partner Danny Burke, portrayed by Gary Lockwood, hitchhike to Seattle to find work.
The two desperately need money to reclaim their airplane, on which the sheriff has attached a lien. They hitch a ride with a Chinese farmer and his seven-year-old niece, Sue-Lin, played by talented Vicky Tiu.
When business unexpectedly occupies the uncle, Mike takes Sue-Lin on a tour of the World’s Fair, where he meets and falls for nurse Diane Warren, portrayed by Joan O’Brien. When Sue-Lin’s uncle fails to return, Mike takes responsibility for the little girl. Mike’s situation goes from bad to worse when Child Welfare takes Sue-Lin away and Danny inadvertently becomes involved with a smuggling operation. Mike, Danny, and law officials eventually subdue the smugglers. The film ends happily when Sue-Lin finds her uncle and Mike and Diane find each other.