He announced he was quitting playing in June because of a hip injury and was told he would take up a coaching position which is now confirmed.
The 35-year-old has taken up an assistant coach role with England but will mainly work with Saints Academy.
"I'm really pleased to remain at the club and help nurture the future talent," he told the club website.
"I'm here to mentor and develop the youngsters to not only become better players but responsible and professional people too."
Paul Wellens has taken up a player performance coach role at St Helens after his retirement.