Official release from Brisbane Roar
The 19-year-old, who has represented his country at U-20s level, trialled with the Roar squad at the latter end of last season and has returned to Australia to put pen to paper, pending an international clearance.
Do's three-year contract will keep him at the club until the end of the 2014/15 season.
"He's a very exciting young player," Brisbane Roar Head Coach Rado Vidosic said.
"We felt that we needed another left-footed player with a more direct style of play to compliment what we already have got.
"Now, we've got more combinations we can apply and I'm very excited about that."
The acquisition of Do brings Brisbane's squad number to 20 with one visa spot still left to fill.