The 29-year-old signed a four-year deal with Wigan after completing a medical at the DW Stadium.
Wigan will pay Bolton £4million for the highly-rated goalkeeper, who spent last season on loan with the Latics.
“We are delighted to announce the best possible news for Wigan Athletic in securing Ali permanently,” Wigan manager Roberto Martinez told the club’s official website.
“During his loan at our football club last season, Ali brought a great degree of professionalism in his daily work and put in many outstanding performances in the Premier League.
“Goalkeeping is a very specific position and we are very pleased that we are going to be very strong in this department going into the new season. Being voted player of the season reflects the huge impression that Ali had on the pitch but also the feeling of the supporters towards him.
“After making it really clear that he wanted to play for Wigan Athletic moving forwards we’ve done everything possible to make this happen.
“The chairman and everyone at the football club are delighted that Ali will be staying and I’m sure every single Latics fan will feel extremely proud and be able to enjoy a great day after hearing this news.”
“I am very happy,” Al Habsi said.
“I want to thank everyone at Bolton for helping me get established in this country but I need to be playing first-team football, and hopefully, if I can stay fit and keep doing my best, I will get the chance again at Wigan.
“I think the gaffer is building a really exciting young team here and I am thrilled that I can be part of that again.”
