Having won their two opening games of the season, the Baggies soon fell apart, leading to the sacking of Tony Pulis.
The appointment of Alan Pardew failed to spark an immediate turnaround, West Brom lurching into a winless run so long that only the miserable 2007-2008 Derby County team possess a longer drought in Premier League history.
Pardew secured his first victory in all competitions at Exeter City in the FA Cup last week, and the visit of the Seagulls offered a fine chance to get on a roll - Chris Hughton's men have now failed to score in nine league games on the road this season.
With that in mind, victory will have been in the host's thoughts as soon as the in-demand Jonny Evans headed it into a fourth-minute lead - the Northern Ireland defender showing the likes of Arsenal and Manchester City his value at both ends of the pitch.
The Baggies should have been given a first-half penalty for a blatant Glenn Murray handball, but they kept at their task and Craig Dawson gave them a cushion early in the second half.
Pardew's men remain second-bottom in the table, but have closed to within two points of 17th-place Bournemouth, which visits Arsenal on Monday (AEDT). Despite the defeat, Brighton is still three points above the drop zone, but its toothless away form will concern Hughton.
The Baggies had scored just twice in their previous four home games, but found the net on their first foray forward in the fourth minute.
Matt Phillips's right-wing corner was flicked on at the near post by Jay Rodriguez, catching out Brighton's defence as Evans charged in at the back post to stretch and head home.
An unmarked Dawson headed off target from another Phillips delivery five minutes later and the winger then blasted wide from 30 yards as the host kept pressure on Mat Ryan's goal.
Referee Martin Atkinson had the benefit of VAR assistance as he officiated the EFL Cup semi-final between Chelsea and Arsenal earlier in the week and Pardew may have lamented the technology's absence on the half-hour mark as Murray blatantly blocked Phillips's shot with both arms, only for Atkinson to wave away penalty appeals.
Dawson was in the thick of the action at either end before the break, bravely blocking Lewis Dunk's shot before wasting a one-on-one chance at the other shortly after, Ryan closing the angles sharply.
But the defender would not be denied when presented with a more familiar chance 10 minutes after the interval, Dawson rising above Gaetan Bong to meet Chris Brunt's left-wing set-piece with a downward header that bounced over those guarding the goal-line and in.
Anthony Knockaert blazed Brighton's most presentable chance over, after Ben Foster had come charging off his line, while goalscorers Dawson and Evans had to be withdrawn with apparent injuries, but Pardew was able to celebrate a fine win that could provide the Baggies' season with the launchpad it badly needs.