The announcement on the team's website (www.chargers.com) comes on the heels of the Chargers' upset AFC Divisional playoff loss to the New York Jets Sunday. Terms of the deal were not immediately disclosed.
Turner has a 32-16 regular-season winning record but is just 3-3 in the postseason since arriving in 2007. His previous contract with the team was set to expire after the 2010 season.
"I'm happy for Norv," Chargers quarterback Philip Rivers told the San Diego Tribune. "It's well deserved, and it's great for our football team."
(Writing by Jahmal Corner in Los Angeles; Editing by Peter Rutherford)