Match ends, MK Dons 1, Leeds United 2.
Ten-man MK Dons suffered a fourth straight loss for the first time since December 2009 as Leeds moved into 10th.
The hosts dominated the opening half an hour with Rob Hall, Carl Baker and Josh Murphy all shooting wide.
But it was Leeds who went ahead when Baker brought down Charlie Taylor with Chris Wood converting the penalty, before Taylor made it 2-0.
Samir Carruthers was shown a late red card for a tackle on Stuart Dallas after Simon Church had cut the lead.
Hall had the first notable chance for MK Dons when he smartly beat two Leeds defenders before striking off target.
Murphy, on loan from Norwich, then had two carbon-copy chances for the Dons when he cut inside from the left-wing and curled just wide when attempting to find the far corner of Marco Silvestri's net, before the Leeds goalkeeper denied the same player at the near post.
Karl Robinson's side then had their best chance to go ahead as Hall's shot was tipped onto the woodwork by Silverstri but Sam Gallagher somehow smashed the rebound over.
That miss was to prove costly as Leeds immediately went down the other end and won a penalty when Baker clumsily brought down Taylor and Wood sent David Martin the wrong way to score his fourth goal in six games.
Taylor's run and shot then doubled Leeds' advantage, before MK Dons saw their own appeals for a penalty for handball waved away by referee David Webb.
A low-key second half was sparked into life when Church converted the dangerous Murphy's cross for his first goal for the club.
Despite Carruthers' dismissal, it was the hosts who pushed for an equaliser at the end, but Leeds held firm for their second Championship win of the season.
MK Dons manager Karl Robinson: "The refereeing was atrocious.
"We've played here and we've been the better team. Someone has to say something.
"He should have to tell you why he sent Samir Carruthers off. Then two and-a-half minutes later (Luke) Murphy has a scissor challenge on the 'D', and there's no booking, and it's his eighth challenge of the game.
"We ask for consistency, and integrity, which they give us all the time, but the performance was way below par today I think from the referee."
Leeds United manager Uwe Rosler: "I felt the way we managed the first 15-20 minutes of the second half was very impressive. We went for another goal and we could have easily scored another goal in that period.
"Then the panic button came into play, even with a man more.
"All credit to MK Dons, they made some tactical changes, they put Carl Baker in the right-back position, and he put ball after ball in our box. We found it difficult to get the ball down and play, and use our man advantage.
"You need to find a way to win, even when you're not playing over 90 minutes prettily, and that's what we did."
- 12SpenceSubstituted forBowditchat 73'minutes
- 3LewingtonBooked at 75mins
- 14CarruthersBooked at 78mins
- 38HallSubstituted forReevesat 58'minutes
- 13GallagherSubstituted forChurchat 58'minutes
- 4WoottonBooked at 90mins
- 6CooperBooked at 45mins
- 23L Cook
- 10MowattSubstituted forAdeyemiat 77'minutes
- 2ByramSubstituted forAntenucciat 84'minutes
- 15DallasSubstituted forBellusciat 90+3'minutes
- David Webb
- Shots on Target
Second Half ends, MK Dons 1, Leeds United 2.
Attempt missed. Giuseppe Bellusci (Leeds United) left footed shot from a difficult angle on the left is close, but misses to the left.
Attempt blocked. Lewis Cook (Leeds United) right footed shot from the right side of the box is blocked. Assisted by Mirco Antenucci.
Attempt saved. Antony Kay (MK Dons) header from the centre of the box is saved in the centre of the goal. Assisted by Josh Murphy with a cross.
Corner, MK Dons. Conceded by Liam Cooper.
Attempt missed. Carl Baker (MK Dons) left footed shot from outside the box is high and wide to the left.
Substitution, Leeds United. Giuseppe Bellusci replaces Stuart Dallas.
Corner, MK Dons. Conceded by Scott Wootton.
Scott Wootton (Leeds United) is shown the yellow card for a bad foul.
Josh Murphy (MK Dons) wins a free kick on the left wing.
Foul by Scott Wootton (Leeds United).
Corner, MK Dons. Conceded by Charlie Taylor.
Attempt missed. Chris Wood (Leeds United) right footed shot from the right side of the box is close, but misses to the right. Assisted by Stuart Dallas.
Foul by Dean Bowditch (MK Dons).
Tom Adeyemi (Leeds United) wins a free kick in the defensive half.
Corner, MK Dons. Conceded by Sol Bamba.
Attempt blocked. Josh Murphy (MK Dons) right footed shot from outside the box is blocked. Assisted by Ben Reeves.
Substitution, Leeds United. Mirco Antenucci replaces Sam Byram.
Attempt missed. Dean Lewington (MK Dons) header from the right side of the six yard box is too high. Assisted by Josh Murphy with a cross following a corner.