Stewart, 30, spent the latter half of last season on loan at Stadium MK, but could not help the Dons stay afloat in League One.
Graham Alexander’s side were keen on landing the centre-back as the last piece of their transfer jigsaw this summer and they finally got him on loan.
Upon returning to a club he is familiar with, the Aberdeen star revealed that he is raring to get promoted with MK Dons.
“What can I say, I am back at a fantastic club, with great staff and management team”, Stewart told MK Dons’ in-house media.
“I cannot wait for the challenge of getting promoted together.“
With the Jamaican centre-back in their fold, Alexander’s side are now hoping to see themselves putting in a promotion tilt this season.
MK Dons will face Notts County next weekend and Stewart is likely to feature for the Dons in that game.
The Jamaican centre-back’s contract at Aberdeen is set to expire next summer.
