Alex O'Loughlin is an Australian actor best known for his role as Detective Steve McGarrett in the television series Hawaii Five-0. Born on August 24, 1976, in Canberra, Australia, he began his acting career in the early 2000s and gained recognition for his performances in various films and TV shows. In addition to Hawaii Five-0, O'Loughlin has appeared in other notable projects, including the series Moonlight and Three Rivers. He is also known for his work in the film The Back-up Plan, showcasing his versatility as an actor in both dramatic and romantic roles.