The former Preston striker scored a bagful of goals early last season but lost his form and ended the campaign as a bit-part player. However instead of moving away from the Terriers following the arrival of Luke Beckett he vowed to stay and fight for his place.
A calf injury to Andy Booth opened the door and Abbott was fouled for the penalty opener, despatched by Beckett, and then sealed victory with a clever finish on the stroke of half-time.
Rotherham had started well but didn't know what had hit them and will rue missed chances through the impressive David Hibbert, who is on-loan from Preston. He had two clear-cut chances and hit the bar with a second half header.
Gary Taylor-Fletcher made it 3-0 when he scored a stunner from out wide for his second goal in as many games.
Huddersfield took time to get Saturday's defeat at Gillingham out of their system with the defence showing its soft centre early on. Nathan Clarke, in particular, looked vulnerable to the pace and close control of Hibbert.
The Millers should have gone ahead in the 11th minute when Eugene Bopp played in Hibbert who turned Clarke and tried to place a measured chip over Matt Glennon but his aim was just too high.
The Terriers broke the deadlock in controversial fashion in the 36th minute when former Town striker Delroy Facey tripped Jon Worthington in midfield.
Quick-thinking Worthington snatched the ball and launched the free-kick towards Abbott on the edge of the box. He shrugged off left-back Paul Hurst, but was tugged back in the process, and referee Paul Robinson pointed to the spot as Beckett stepped up to slot home the resulting penalty.
Hibbert almost pulled Rotherham level with a free header from a corner but Mark Hudson cleared off the line and in first half stoppage time Town sealed the win. Danny Adams sent over a driven free-kick from the left and Abbott slipped in ahead of Pablo Mills to slot home.
Just after the break Hibbert beat Glennon but saw his header come back off the bar.
Minutes later it became clear it was not Rotherham's night when Clarke lost his footing and presented a simple chance to Hibbert, but he fired over with the goal at his mercy.
Taylor-Fletcher showed him how to do it with a brilliant effort 11 minutes from time to seal a good victory for Peter Jackson's men.