The Saints have signed Ratten to a three-year deal, with club president Andrew Bassat thrilled to have made the announcement.
“We were able to evaluate Brett across six weeks as interim coach and through the opportunities he had to present to the panel,” Bassat said.
“At every stage, he gave us great confidence that he is the right person to lead our football program.
“His greatest strength is building relationships with players, coaches and staff, and we have seen that first-hand during his time at the Saints.
“He brings a great balance in building relationships and creating a positive environment, while also driving uncompromising standards.
“We know as a football club we have to lift in a number of areas to achieve the consistency required to play finals football.
“We have a young, talented group of men who we need to develop, add to, and inspire to take their football to another level.
“Brett is the right person to lead our coaching group in driving that improvement, and we look forward to seeing him take charge as Senior Coach for the next three years.”