The 41-year-old is the current assistant coach at the Sydney Roosters with specific focus on attack.
He is also the Head Coach of the Junior Kangaroos.
“We are delighted to secure Justin; he is widely experienced and has a track record of coaching at the highest level.” Saints Chief Executive Mike Rush said. “He impressed us with his knowledge of the British game and his work with younger players.
“In his role as head of the Junior Kangaroos, a position he has held for three seasons, he has done a superb job in nurturing young talent and developing the next wave of Australian Internationals.
“During the process Justin clearly identified himself as an attack minded coach and the importance of the transition between defence and attack.
“He also understands the club and our philosophy which is important moving forward.”
Justin has been appointed after an exhaustive process.
He said: “I’m excited about the opportunity to be the head coach of St Helens. The club has a rich and proud history and I am very grateful to have been given the opportunity.
“St Helens are one of the top teams in the Super League competition with a history of success. I will be working hard to continue that tradition and I cannot wait to get started.”
Justin was part of the Roosters coaching team that guided the club to the Minor Premiership in 2015.
He also coached Sydney when they faced Saints in the 2016 World Club Series.
Justin’s previous coaching experience includes working with the Canterbury Bulldogs, St George-Illawarra and the Parramatta Eels.
He also played as a half for Newcastle Knights, Penrith Panthers and Sydney Roosters during his own playing career.
The Club expects Justin to arrive in this country as soon as possible, visa pending.
He has signed a two-and-a-half year contract.
Both Jamahl Lolesi and Sean Long will remain as part of Justin’s coaching team.
This will also allow Derek Traynor to return his attention back to the Academy set-up.
“Justin has made a significant contribution to the Roosters since he joined us as an Assistant Coach in 2014,” said Roosters Head Coach, Trent Robinson.
“Not only is Justin a great coach, he’s also a terrific person, and I’d personally like to thank him for his efforts, commitment and friendship.
“This is an exciting opportunity for Justin, and on behalf of everyone involved with the Roosters, we wish Justin, his wife Nat and their young family all the very best.”