The visitors took the lead following a bright start from James Vaughan, with the 24-year-old creating a series of early chances before scoring in the 10th minute.
However, a dominant display from the hosts resulted in three goals for Majewski and one for on-loan defender Elliott Ward before half time, to put Forest in a strong position.
Majewski's first levelled the scores in the 21st minute, before two shots from close range towards the end of the half sealed the hat-trick.
Huddersfield failed to create many chances as they looked to reduce their opponents' advantage late in the game.
Darius Henderson ensured that Forest finished with a flourish, adding their sixth goal of the game deep into stoppage time to round off an emphatic win at the City Ground.