The 19-year-old, a graduate of the Australian Institute of Sport, made 25 appearances for the club in his debut Hyundai A-League season.
Head coach John Aloisi: "It's a fantastic opportunity for Curtis.
"Newcastle United is one of the biggest clubs in the United Kingdom, and we are absolutely delighted he has the opportunity to test his wares on such a stage."
Good, a central defender, had a successful trial at Newcastle late last season.
United are understood to have agreed an initial fee of £500,000.