The Matterhorn was an actual set location and actors and crew were required to climb the summit for filming.
James MacArthur made the film during his summer break from Harvard University where he was studying history.
Part of this movie was filmed in Zermatt, Switzerland. To the very day you can see where the Disney production company painted patterns on the outside of already existing chalets. These were added to be more in line with how Americans pictured an alpine town in the Swiss mountains. To the very day, when folks see the painted-on designs, many assume that they are originals from hundreds of years ago, however it was Disney who put them there in the late 1950's.
The Matterhorn Bobsleds attraction at Disneyland Park at the Disneyland Resort in Anaheim, California is inspired by this movie.
The filming of this movie is chronicled in Walt Disney Presents/Perilous Assignment.
Helen Hayes: James MacArthur's mother, appears uncredited as a tourist leaving the hotel where Rudi works.