The Spaniard has penned a one-year deal at the DW Stadium.
Jordi Gomez has a shot which leads to Danny Graham scoring the first goal for Sunderland
Gomez had spent two years on Wearside after joining from Wigan in 2014 and, despite having a year left on his contract with Sunderland, he has decided to return to his previous club.
The Latics fan favourite made the move to the DW Stadium in 2009 from Espanyol, and he enjoyed five successful years and was part of the side which won the FA Cup in 2013.
Speaking to the club's official website, Wigan manager Gary Caldwell, a former teammate of Gomez's, expressed his happiness with the club's latest acquisition.
Wigan's Jordi Gomez celebrates scoring their first goal
‘There have been rumours about this one all summer, and we have had to work really hard to get him here within our budget," Caldwell said.
“Football-wise, we all know what Jordi can do, and at 31 he is still at the peak of his abilities.
"His quality on the ball is second to none and he will be able to pass on his knowledge and experience on and off the fields to help the younger members of the squad.
"He adds great competition to the squad and we are delighted to have got him.”
Blackburn Rovers' Jordi Gomez in action with Wolverhampton Wanderers' Kortney Hause
Gomez scored 28 goals in 162 appearances in his first spell at Wigan, but had a mixed two years at Sunderland.
Despite being a mainstay in the Black Cats' starting 11 in his first season, the Barcelona youth graduate turned out just six times in all competitions for the club last year.
Gomez makes for a good acquisition to strengthen Wigan's resolve after an encouraging start to life back in the Championship, where they have gained four points from their first three league games this season.
Wigan Athletic manager Gary Caldwell