Steven Mounie scored twice in the first half to hand David Wagner's side all three points from the first ever top-flight meeting between the two sides, lifting the Terriers up to 11th in the table in the process.
Brighton, meanwhile, drop down to 13th having now failed to win any of their last five outings, leaving the Seagulls only four points clear of the relegation zone.
It was Chris Hughton's side who were the first to come close on a snowy afternoon in Yorkshire, with Jonas Lossl called into action after just five minutes to deny an early header from the in-form Glenn Murray.
Huddersfield were quick to respond at the other end, though, and Mounie's first sight of goal arrived just three minutes later when his low volley from the edge of the area was kept out by Mat Ryan.
Mounie did get the opener shortly after that, breaking the deadlock in the 12th minute with his first ever goal at the John Smith's Stadium when he tapped Christopher Schindler's flick-on in at the back post.
Brighton struggled to produce a response after falling behind, and it wasn't until 10 minutes before half time that either side had another effort of note when Tom Ince's search for a first league goal of the season continued as he dragged a shot wide of the target.
The hosts did have their second of the match with two minutes of the half remaining, though, and again it was Mounie who did the damage when he nodded his finish past Ryan from inside the area after Aaron Mooy and Mathias Jorgensen had combined to find him.
Huddersfield continued to push for a third goal upon the restart and were only denied it by a fine save from Ryan 10 minutes into the second half, when he thwarted Ince from point-blank range after Tommy Smith had played a dangerous low ball into the box.
The Terriers refused to relent, though, and came close again twice in quick succession when first Mounie blazed a hat-trick chance over the crossbar before Ryan made another stop to deny a powerful Elias Kachunga effort at his near post.
Jorgensen then failed to make the most of some slack marking from the resulting corner, before Kachunga headed narrowly wide from a Mooy cross moments later.
Huddersfield were back on the front foot again soon enough, and Smith was the latest to threaten a third goal when his curling effort drifted just past the upright, before Ince drilled one over the crossbar as the home side's pressure continued to grow.
Brighton did manage to stem the tide in the closing stages of the match, but there was little sign of a fightback from the visitors as they fell to back-to-back defeats for the first time since the opening two games of the season.
Huddersfield, meanwhile, pick up their first win in more than a month to climb above the Seagulls and five points clear of the relegation zone.
Huddersfield Town (4-2-3-1): Lossl; Smith, Jorgensen, Schindler, Lowe; Mooy, Hogg; Kachunga (Williams, 89'), Ince (Lolley, 87'), Quander; Mounie (Depoitre, 85')
Brighton & Hove Albion (4-4-1-1): Ryan; Bruno, Duffy, Dunk, Suttner; Schelotto (March, 46'), Stephens, Propper, Brown (Hemed, 73'); Gross (Izquierdo, 63'); Murray