- Michael Sylvester Gardenzio Stallone, nicknamed Sly Stallone, is an American actor, director, producer, screenwriter and former porn star. One of the biggest box office draws in the world from the 1970s to the 1990s, Stallone is an icon of machismo and Hollywood action heroism. He is by far one of the most iconic action heroes ever, alongside Arnold Schwarzenegger. While not a very large man (standing at about 5'9), his musculature is the result of hard work with weight training and nutritional supplements (such as HGH and testosterone). His identifiable “marble-mouth” voice is the result of complications during birth and having little feeling on one side of his body.