Sunderland, who had not won at home in the league for almost four months, made a positive start and deservedly took the lead when Connor Wickham headed home from Anthony Reveillere’s cross in the 20th minute.
Defoe doubled the advantage 14 minutes later as Patrick van Aanholt crossed for him to finish from close range.
Burnley improved after the break but were unable to get back into the match after surprisingly taking off top scorer Danny Ings with just an hour gone.
Ings, who has been linked with a move away from Turf Moor in this transfer window, looked frustrated with the decision and could only watch from the dugout as his side slumped to defeat.
While it was a frustrating afternoon for Ings and Burnley, it was a much-needed victory at home for Sunderland after they were booed off by some of their fans following their FA Cup draw with Fulham last weekend.
Despite their poor recent home record, the Black Cats started with purpose as they pressed the visitors high up the pitch and allowed Burnley little time in possession.
Still, the first real chance of the match fell the visitors’ way in the 17th minute as Ashley Barnes headed wide from David Jones’ free-kick from the right.
A few minutes later Sunderland took the lead when referee Lee Mason played a good advantage to allow Sebastian Larsson to thread a ball through for Reveillere, who crossed for Wickham to head home.
It was no more than the Black Cats deserved and they doubled their advantage in the 35th minute as Van Aanholt set up Defoe to score his first goal for the club.
The full-back looked to be right in line with the last man as he was played in by Jordi Gomez and made the most of the call as he put the ball into the six-yard box for Defoe to finish.
Jones and Barnes both tried their luck from range for Burnley without testing Costel Pantilimon but Defoe should have put the game to bed early in the second half as he mis-hit a shot from a good position.
Burnley enjoyed a greater share of the possession after the break but struggled to break down a solid Black Cats defence.
Barnes spurned their best chance when he headed into the ground from close range while Dyche opted to take off Ings and George Boyd on the hour mark.
Poyet also replaced Defoe and Wickham with 15 minutes to go but Sunderland saw the rest of the match out comfortably to secure victory.
Soccer Saturday reaction – Charlie Nicholas
“I was surprised Ings was taken off, I was expecting Vokes to come on and partner him and see if they could get the old routine going again. I know Barnes has done really well but I just think maybe they could have got that partnership together and seen if they could get a little sparkle. Ings was having to do the majority of the hard graft and it might have taken that burden away from him.
“I thought there some signs of fatigue from Burnley. There was just 10% missing and at this level that means you are going to struggle.”
Sunderland: Pantilimon (6), Reveillere (7), Vergini (6), O’Shea (6), Van Aanholt (7), Bridcutt (6), Gomez (6), Johnson (7), Larsson (6), Wickham (7), Defoe (7).
Subs: Alvarez (5), Fletcher (6), Graham (6).
Burnley: Heaton (6), Trippier (5), Keane (5), Shackell (5), Mee (6), Arfield (6), Boyd (6), Jones (5), Marney (6), Barnes (5), Ings (5).
Subs: Wallace (5), Jutkiewicz (5), Vokes (5).
Man of the match: Jermain Defoe.