Duke Kahanamoku was born in Hawaii in 1890. He was one of nine children born at a time when Hawaii was still a kingdom, before the overthrow by the United States. He was taught at a very early age how to swim and became an incredible swimmer. So much so that he began competing in the olympics and winning several medals shattering records as he went. He first competed as part of the US swim team in 1912 at the Stockholm Sweden competitions. Then again in 1920 and 1932. After he won several competitions he then ventured into acting (staring in over 20 films/shows), and later became a police officer. When he first came on the scene in surfing and acting he was discriminated against, and although many loved him he was not featured prominently in Hollywood films.
But, he is credited for is giving surfing to audiences in Australia in the early 1900's which no one outside of Hawaii had ever seen. He inspired many young people in Hawaii and across the world. It is said that he would perform tricks such as standing on his head, walking the board, and surfing with power and grace. His contribution brought surfing to the world and it exploded. He has been recognized as a pioneer, a kind man, a hero, and has been inducted into both the swimming and surfing hall of fame. To this day there is a surfing competition named in his honor.
Sources: Wikipedia, Duke Surfer of the Century, Duke Foundation