Nathan Fillion is a Canadian-American actor best known for his role as Malcolm Reynolds in the popular television series Firefly. He has also gained fame for his portrayal of Richard Castle in the long-running show Castle, where he played a mystery novelist who helps the police solve crimes. Born on March 27, 1971, in Edmonton, Alberta, Fillion began his career in television with roles in soap operas like One Life to Live. Over the years, he has appeared in various films and TV shows, becoming a beloved figure in the science fiction and fantasy genres.