McLeod tapped in the opener just four minutes after coming on as a 36th-minute substitute before superb half-volleys from Daniel Powell and substitute Stephen Gleeson sealed the win.
Milton Keynes were twice denied by the woodwork in a dominant first-half display, with Dean Bowditch curling a 25-yard free-kick against the post and Ryan Lowe heading against the crossbar from close range.
Doncaster midfielder James Harper then had a goal disallowed for a shove before McLeod put the Dons ahead in the 40th minute, slotting in the rebound after Lowe's fierce shot had been parried by goalkeeper Gary Woods.
Powell celebrated his new two-year contract by doubling the Dons' lead in the 56th minute, swivelling to fire a stunning left-footed half-volley into the top corner from the edge of the box.
Rovers striker James Coppinger had a shot deflected just wide and then fired another decent chance too close to Dons goalkeeper Ian McLoughlin as the visitors rallied.
But Gleeson marked his return from a three-month injury lay-off by scoring with his first touch seven minutes from the end, blasting McLeod's knock-down into the corner as Doncaster missed the chance to go four points clear at the top.
- Sports & Recreation
- Stephen Gleeson
- Daniel Powell