Terms of the deal weren't released, but the (Minneapolis) Star Tribune reported it was for $5.7 million.
The 28-year-old netminder, who has served as a backup to Niklas Backstrom, was set to become an unrestricted free agent July 1.
After missing the entire 2010-11 season with torn knee ligaments, he returned in the recently completed campaign to go 13-12-4 with a 2.62 goals against average in 34 games.
Harding also underwent season-ending hip surgery in 2009-10.
He has compiled a 41-51-8 record with a 2.65 GAA over 117 career contests with the Wild.