The five-year extension is worth $43 million, including $20 million in guaranteed money and bonuses, a league source told ESPN NFL Insider Adam Schefter.
The team announced McCourty signed the five-year extension Thursday before the Titans (1-1) hosted the Arizona Cardinals (1-2).
A sixth-round pick in 2009 out of Rutgers, McCourty has started 24 of 42 career games with 182 tackles, four interceptions, a sack, two forced fumbles and a fumble recovery. He set a career-high with 107 tackles last season and led the team with 13 passes defended. His two interceptions tied for the team lead.
He scored his first career touchdown last season by recovering a blocked punt in the end zone Oct. 20 against Indianapolis.
Information from ESPN NFL Insider Adam Schefter and The Associated Press was used in this report.