Cowie was believed to be a target for a number of Championship clubs, and it was his decision to reject a new contract from Cardiff which allowed Wigan manager Uwe Rosler to add another option to his squad.
"After we lost Jordi Gomez, Jack Collison, Josh McEachran, added to the longer-term injuries we've had with Ben [Watson] and Chris [McCann], I wanted to bring in an energetic player with experience who knows all about getting out of this league," Rosler told the club's official website.
"Don also played over 20 games last season in the Premier League; he's 31 but he's an extremely professional person and I've known about him for quite some time.
"From his training regime to the way he lives and breathes football he has the attributes to allow him to play football until his late 30s."
Rangers, Blackburn Rovers and Watford were all reported to be interested in Cowie.