French-born model-turned-actress Sylvia Lopez was already ill with leukemia at the time of filming. She was only able to complete one more film in 1959, and died at age 26 while working on another film.
After the release of the movie, in his Summer 1959 (Vol 9 No 2) issue of 'Physique Pictorial' (for which a still of the movie was used as the cover), Bob Mizer wrote: ''Steve Reeves has become the hero of Millions of Europeans for his role in HERCULES, and even in the more blase United States is becoming known to millions who are completely unaware of bodybuilding. Steve has devoted his whole life to having a magnificent body, and though he was no skinny walking as a youth of 16, no one would then have believed he could ever become the giant he is today. He leads on extremely austere life, doesnt (sic) smoke, drink, use stimulants but rather strongly emphasizes health foods. While working on the picture Hercules he would retire for bed at 6 pm, and was up on dawn. He likes to study serious subjects such as philosophy and since he is often very succinct and non-social, only the few privileged people who really know him realize that here is a man with a mammoth mind as well as a super body.''
Composer Enzo Masetti retired after completing the score for this film, in which he uses material from his previous work, Hercules (1958). These two scores became the most famous of his compositions, internationally.
Joseph E. Levine was so confident in the success of his release of Hercules (1958) in the US that he bought the distribution rights to this film in advance and even visited the set as it was being shot.
The love theme for Hercules and Onfale was originally composed by Enzo Masetti for Outlaw Girl (1950).