The 32-year old former Celtic, Manchester United, Sunderland, QPR and Hibernian midfielder has spent the past two seasons with the Glory but will now continue his career with two-time champions the Roar after signing a two-year deal with the option for a third.
"I'm very happy to be joining a club with such a strong football culture both on and off the pitch," Miller said.
"I know how proud and passionate Brisbane Roar fans are and I look forward to proving to them I am worthy of wearing this orange jersey.
"My family were a huge part in my decision to sign for Brisbane and the close-knit nature of the playing group and the whole club made that decision easier for me.
"I am confident I can make a difference to this Roar team and I can't wait for pre-season to begin."