Mr. Miyagi has a deep philosophical knowledge of life and has extraordinary martial arts skill. The film hints repeatedly that the character could be a descendant of Chojun Miyagi (1888—1953), the legendary founder of Goju-ryu Karate, as Miyagi refers to his style of karate as Miyagi-do karate. Also, Mr. Miyagi's knowledge of Chinese acupressure techniques show that the style of karate he practices is very likely Goju-ryu. Mr. Miyagi explains in the second film that the founder of his family's style learned his skills in China, where Chojun Miyagi indeed travelled, although the film character refers to an involuntary travel due to unfortunate winds. Lastly, the real Chojun Miyagi was indeed able to catch flies with chopsticks, something Mr. Miyagi tries to do throughout the series. Nonetheless, several other details, especially in the second film, rule out the relation: Mr. Miyagi tells that his Karate style is centuries old, but the founder was born only in 1888. He himself lived in Okinawa during the lifetime of Chojun Miyagi, but never mentions him. Chojun Miyagi learned karate in Japan and only later travelled to China, unlike the forefather of the film character. The authentic Miyagi also opened schools to teach others his style, whereas the film dynasty passed karate on only to their own sons (and exceptionally a very good friend of their sons'). Finally, the film dynasty were fishermen with the exception of the "Mr. Miyagi" himself, but Chojun Miyagi dedicated his professional life to Karate.
An Okinawan Japanese immigrant to the United States, Mr. Miyagi was most likely born on April 11, 1923 (inferred from his immigration to the U.S. and war service). He had learned karate originally from his father, who had been a fisherman. He came to the United States after leaving Okinawa to avoid a fight to the death between him and his former best friend Sato. Miyagi was in love with a young woman named Yukie from his village. Yukie however was arranged to marry Sato. Miyagi rebuked the marriage in front of the whole village, claiming that he and Yukie were in love, and Miyagi was set to go against tradition and marry Yukie anyway. This greatly dishonored Sato, who challenged Miyagi to a fight to the death. To avoid the fight - by the conduct of karate - Miyagi left Okinawa and Yukie behind. It was not until 1985 when Miyagi's father (also Sato's sensei) was dying that Miyagi returned to his village. Upon his return, Miyagi was reunited with Yukie. After Miyagi's father passed away, Yukie revealed to Miyagi that his father was proud that his son didn't take up Sato's challenge and that Miyagi indeed did the right thing. However, also on this return, Miyagi was eventually forced to face his history with Sato. Sato relentlessly tried to have Miyagi accept his challenge to fight, but after Miyagi saved Sato from death during a hurricane attack, Sato relented and he and Miyagi became friends again.
After leaving Okinawa, Miyagi met and married another woman. Miyagi and his wife were soon expecting their first born when Mrs. Miyagi was interned in the Manzanar Japanese internment camp
in California during World War II
. During this time, Miyagi joined the U.S. Army's 442nd Regimental Combat Team
and fought in Europe
, eventually rising to the rank of Staff Sergeant
and being awarded the Medal of Honor
, Distinguished Service Cross
, Silver Star
, Bronze Star
, and multiple Purple Hearts
. During his service, Mrs. Miyagi and their son died in the Manzanar camp due to complications during childbirth. Though normally a very disciplined and modest man, he is shown in one scene in the first movie in a maudlin state of extreme drunkenness on the anniversary of his son's birth and wife and son's death. (The loss of his family, and the death of Daniel's father prior to the beginning of the movie, provide a thematic justification of Miyagi and Daniel's relationship as surrogate father and son).