The title character was based on the author's daughter, Kathy Kohner-Zuckerman, and her adventures growing up in the surf culture at the beach in Malibu during the 1950's. She is still petite, healthy and attractive and lives in Pacific Palisades with her husband. And yes, there was a "Moondoggie", who lives in California and is an artist.
Cliff Robertson grew up in La Jolla, California, where he is well known for his surfing ability. Robertson can be clearly seen surfing in the movie. However, in a 1978 interview on 60 Minutes (1968), Tom Laughlin admitted he suffered tremendously during the surfing scenes.
Because of the widespread popularity of this movie and the book it was based on, the real-life Gidget, Kathy Kohner, was ranked number 7 in Surfer Magazine's 40th anniversary issue's list of the 25 Most Influential Surfers of All Time.
Following Sandra Dee's passing in February 2005, some of her co-stars and friends appeared on Larry King Live (1985) to pay tribute to her. James Darren revealed that he had a crush on her during filming but couldn't get close to her because her mother was always there.
The producer wanted Elvis Presley to play the leading male role but the studio declined because Presley was at the time too expensive.