Bruce Lee.
Great Lee, also known as Bruce Lee or a Bruce Lee imposter, is a character that heavily looks like Bruce Lee, the famous martial artist. The first time he appeared was in the 21st Budokai against Krillin, in which he tried to Dragon Stomp Krillin. Krillin simply got up and laughed it off. Afraid, the Bruce Lee imposter forfeited the match. Later he was seen in west city charging fighters money to fight him, after defeating a man with a shaved head he takes on Goku and takes several hits to the face before giving up in the same fashion as he did aganst Krillin. He seemed to have gotten stronger, however when he is seen again his voice was not the same as before and he wears blue boxing gloves. When he fought Krillin it might have been assumed that he used kung fu, however when he fought goku a spectator says that he is a master of kickboxing. It's possible there has been two impersonators or likely he had gone through slight changes.
Production
Akira Toriyama was a fan of Hong Kong martial arts films, particularly Bruce Lee films such as Enter the Dragon (1973) and Jackie Chan films such as Drunken Master (1978), and wanted to create a manga inspired by martial arts films. This led to Toriyama creating the 1983 one-shot manga Dragon Boy, which he later redeveloped into Dragon Ball. Toriyama wanted to create a story with the basic theme of Journey to the West, but with "a little kung fu." The title Dragon Ball was inspired by Enter the Dragon and later Bruceploitation knockoff kung fu films which frequently had the word "Dragon" in the title. The character Great Lee in the manga is a parody of the Bruceploitation genre and the numerous Bruce Lee impersonators.
Later in the series, adult Goku's pose and piercing glare in Super Saiyan form was based on the real-life Bruce Lee.