Dons provided United with a guard of honour prior to kick-off and were unable to match them over the 90 minutes.
Leon Clarke continued his rich vein of form to give Blades the lead on the stroke of half-time.
Sharp then capitalised on a slip in the Dons defence to smash home his 200th goal of his career.
The division's leading marksmen then added a second to take his tally for the season to 29, slamming home with ten minutes remaining.
The victory takes United closer to the coveted 100-point mark in League One, with the title and promotion back to the Championship already in the bag.
MK Dons: Nicholls (Martin 90), Baldock, Lewington, Walsh, Upson, Potter (Thomas-Asante 73), O'Keefe, Williams, Agard, Muirhead (Reeves 86), Barnes. Not used: Martin, Rasulo, Brittain, Downing, Tilney.
Sheffield United: Moore, Basham, Wilson (Done 62), O'Connell, Freeman (Chapman 87), Lafferty, Coutts, Fleck, Duffy (Carruthers 56), Clarke, Sharp. Not used: Long, McNulty, Scougall. Referee: John Brooks (Leicestershire).