Jin Yong is a pseudonym or pen name that he chose to write under. The reason he chose this specific moniker is because when you combine the two Chinese characters Jin and Yong, you get the last character of his real name. He was born Cha Leung Yung (surname is Cha) or Louis Cha in Hangzhou. He first worked as faculty in first Chunking and then Dongwu University. He then started what would be a career in newspapers while moonlighting in the film industry. He started writing fiction, which was first published in a serialized format in newspapers (similar to the situation how European & American writers published in the 1800s). Shortly afterwards started a newspaper, Ming Pao Daily News, which became highly successful (its success was helped with the fact that Jin Yong started publishing his fiction only in Ming Pao). He then started racking up accolades and acclaim until retiring. But even after retirement, he is still raking in the money from the runaway success of his writings. He has been especially popular recently because of the recently lifted ban on his writings in China (due to typical Communist paranoia about the implications of his choice of title for one of his novel series.)
He is considered by most, if not all, to be the best wuxia writer out there. Since he has also vowed not to write any more novel series, this is indeed a great loss to the genre. However, he has spent the last decade or so revising and editing his existant works. In some cases, the revisions have been major.** Most of his works is only available in Asian languages. There have been a few attempts at professionally translated English editions but there have been mixed results. Fans have started translations on their own but the works are long and numerous.
A nice thing to note about Jin Yong is that he is very scholarly and his type of wuxia fiction can also be labelled as historical fiction. His stories blend history with fiction with great believability and depth. He has a vast knowledge of Chinese history and culture, which he uses to great effect in his works. One notable hobby he has is the game of Go, which is also something I am interested in. He slips in many references to it as it is also one of the four arts the ancient (or modern) Chinese scholar should know (the rest are: calligraphy, painting and music). He is also obviously very skilled in the use of the Chinese language, often choosing to use a more archaic turn of phrase to promote the sense of being in the long gone past in his stories. His works are worthy of study and in fact, there are scholars who devote their time to studying and researching his works (it is called Jin Yong Studies or Jinology).