The 26-year-old is serving a 14-month suspension imposed by UK Anti-Doping after testing positive for cocaine. The suspension was confirmed in April but back-dated to September 2017, when he took the test. He was later sacked by his club Castleford.
Wigan confirmed he had signed a four-year deal and will be free to join the club officially on November 8. The club said he would be permitted to train with them two months before that.
The club’s chairman Ian Lenagan said: “This wasn’t a decision that we made lightly. We recognise the serious nature of this incident and our choice in offering this opportunity should not be seen as condoning his actions in any way.”
Lenagan added: “We had extensive conversations with Zak and his family before making our offer.
“We encountered a man who, after eight months of reflection, openly admits that he has made a series of significantly poor decisions over the past few years. Crucially, we also saw someone who recognises that this is the final opportunity to focus on delivering the achievements his talent should generate.”
Hardaker has won the Super League Grand Final and Challenge Cup twice each, all with Leeds.
He won the Super League’s Man of Steel award in 2015.
Hardaker joined Castleford initially on loan in the autumn of 2016 before making the move permanent in June 2017.
He was left out of the Tigers’ Grand Final squad in October 2017 to face his old club Leeds after the adverse drugs test came to light.
“I have had the experiences in business and sport of offering contrite individuals the final opportunity and environment to learn from their mistakes with some notable successes and occasional failures,” Lenagan said.
“Wigan are giving Zak Hardaker that platform to repay the faith his family have shown him. My team at Wigan will manage, mentor and test him through this period of rehabilitation and development and, hopefully, guide him back to being one of the best players in Super League.”
Wigan coach Shaun Wane added: “Zak is an outstanding competitor and a hugely talented individual who will understand the culture at our club. He is the opposition name who, when we preview his team, is always the main danger. Now he is on our team and that is pleasing for everyone involved.”