After a sketchy couple of weeks for the Hammers, a red-hot start from talisman Bowen arrived right on time for under-pressure boss David Moyes.
The England international netted twice in as many minutes for the hosts, breaking the deadlock early doors with a thunderous effort from inside the penalty area.
Looking like a changed side, West Ham continued to attack Brentford, with Bowen doubling his tally moments later, this time converting off a pinpoint Vladimír Coufal cutback.
It had looked as if West Ham would run away with the contest after the lightning-quick start, but much to the annoyance of Moyes, Brentford reduced the deficit to just one goal midway through the first half.
Sloppiness at the back would cost the hosts, with Keane Lewis-Potter capitalising on a mistake, before slipping through Neal Maupay, who made no mistake with a killer finish.
It had left West Ham looking a little uncomfortable towards the end of the first half, and a lull in the atmosphere at the beginning of the second looked as though it could present Brentford with a route back into the game.
That door was firmly shut on the hour mark when Bowen wrapped up his hat-trick, nodding home a delicious clipped cross from teammate Mohammed Kudus.
But while Bowen was the standout performer from the night’s action, the best goal of the evening went the way of Emerson Palmieri, who leathered home a wonder strike from the best part of 25 yards out to give the hosts genuine breathing space.
There was still time for Brentford to claw back some dignity late on, with substitute Yoane Wissa curling home a stylish finish from the edge of the box.
A pair of fantastic saves from Alphonse Areola in stoppage time kept the Hammers comfortable, as they ended their worst start to a calendar year since 2007 with the win.
As for Brentford, the defeat coupled with news that Everton had been handed back four points from their 10-point deduction makes it a miserable Monday for the Bees, who now sit a worrying five points clear of the drop zone.
Flashscore Man of the Match: Jarrod Bowen (West Ham United)
