Financial terms were not disclosed.
Wesley, 34, was an unrestricted free agent. He finished the 2002-03 season with Toronto, which acquired him from Carolina on March 9 for a second-round draft pick in 2004.
In seven regular-season games with the Maple Leafs, he has three assists. He also appeared in five playoff games, recording one assist.
Wesley had been with the Carolina franchise since 1994-95, joining the Hartford Whalers for the abbreviated season. He also has played for the Boston Bruins during a 16-year career, totaling 47 goals and 143 assists in 629 games.
General Manager Jim Rutherford is looking for his leadership again next season.
"He's been an important part of our team and a leader on the ice for a long time," Rutherford said. "We believe his return solidifies our defense heading into this season."
Carolina finished last in the NHL last season.