The 33-year-old was awarded an extended three-year contract on Thursday.
At the age of 33 Defoe enjoyed his most successful campaign in recent years by netting 18 goals in all competitions for a struggling Black Cats side.
That form did not earn him a recall to the England side for Euro 2016 squad, but it has persuaded the Wearside club to award him new terms even though he still had two years left of his previous contract.
The new deal ties the former Three Lions international to the Stadium of Light until 2019, at which time he will be 36 and surely in the very twilight of his career.
The move could be seen as a big gamble for a club perennially battling relegation, but Defoe was a priceless player for Sunderland this season and deserves to have faith shown in him to continue his resurgence.
Certainly, the club's supporters don't seem concerned about the striker's advancing age, with the former Tottenham Hotspur man arguably in some of the best form of his career last season.
In fact, the reaction on Twitter was overwhelmingly positive as Black Cats fans celebrate the proven goalscorer's decision to commit his long-term future.
Class news about Defoe— Claire Wigham (@safcclaire) June 9, 2016
Defoe rewarded for his excellent contribution, just how it should be! #SAFC— Liam Kennedy (@KennaSAFC) June 9, 2016
Chuffed to bits that Jermaine Defoe has signed for another 3 years #SAFC— Steven ward (@Safcftm) June 9, 2016
Jermain Defoe signing a new contract is just beautiful news #safc— Thomas Rutherford (@Tomrud23) June 9, 2016
It's good that Defoe has committed to us. After the season he's had, he's proved he's not finished. Would've been plenty of takers— Lewis (@newtsfever) June 9, 2016
Defoe finishing his career with us. Love it— Eddy Gray (@EGR4Y) June 9, 2016
Defoe signing a new contract has made our transfer window already :) ❤#safc— Andy Meikle (@andymeikle1) June 9, 2016
Defoe signing a contract extension is a class signing in itself. Unreal bit of business.— Adam Dodsworth (@dodsy_adam) June 9, 2016
Defoe and what he gives a team cannot be taught. He'll be playing into his forties. Great that we've awarded him with an improved deal.— Roker Report (@RokerReport) June 9, 2016
Defoe deal makes sense to me, yes he'll be close to 37, but his lifestyle will probably allow him to play to that age no problem at all— Lozzy (@L0ZZYL) June 9, 2016