Bolton, who were beaten for only the second time this season, simply had no answer to the skills of the Hungarian international captain.
They briefly gave themselves hope when substitute Stelios Giannakopoulos scored direct from a 30-yard free-kick.
Albion were, however, able to hold on and secure a timely victory for Megson who had spent the build-up to the game having to deal with speculation that it could have been his last in charge.
But chairman Jeremy Peace spoke out in support of Megson on the eve of the match, dismissing rumours that Sir Bobby Robson had been lined up to take over.
Gera inspired Albion and gave Megson more breathing space as the Baggies lifted themselves out of the relegation zone.
Albion enjoyed a purple patch in the opening ten minutes and should really have made their domination pay only to be let down by their finishing.
Gera twice went close with long-range drives before Bolton enjoyed a double let-off in the tenth minute.
Gary Speed was perfectly placed on the goalline to clear a header from Albion skipper Darren Moore before Gera saw his follow-up shot blocked by Bruno N'Gotty.
Jonathan Greening then wasted another opening for Albion when he headed over the bar in the 21st minute.
Their profligacy in front of goal should have been punished but Bolton proved no more clinical than Albion when they were presented with a golden chance to break the deadlock.
Ricardo Gardner weaved his way past Bernt Haas and Gera before cutting into the Albion area in the 25th minute.
Albion goalkeeper Russell Hoult was unable to hold his shot and the loose ball fell to Kevin Nolan just two yards out.
But Nolan was unable to get his shot on target and was forced to look on in disbelief as the ball bounced to safety off the post.
In Gera, Albion possessed by far the liveliest player and Bolton struggled to keep him in check.
He was again only inches away from breaking the deadlock on the stroke of half-time when his 20-yard drive whistled past the post after he had collected a misplaced clearance by N'Gotty.
Having been to the fore so much in the first half it was no surprise that when Albion did finally make their pressure pay it was Gera who was the architect.
Picked out by a pass from Moore, he cut in from the right wing and delivered the most accurate of crosses that was deftly flicked past Jussi Jaaskelainen by Kanu from six yards.
Gera deserved a goal of his own for his display and he only had another nine minutes to get his just reward.
Bolton were caught sleeping at a corner and when Greening floated over his cross, Gera rose at the near post to bury a powerful corner.
Albion looked set to cruise to their first Premiership win at the eighth attempt, but they were forced to endure a nervous final 15 minutes after Giannakopoulos scored in bizarre style.
His free-kick flew into the area and deceived his team-mates and the Albion defence alike before nestling in the bottom corner of the net.
Bolton could have then snatched a point eight minutes from time only for Radhi Jaidi to volley over the bar from close range.
MAN OF THE MATCH: Zoltan Gera (West Brom) - Produced an outstanding display, creating the opening goal for Kanu before sealing the victory with his second goal for the club following his £1.5million summer move from Ferencvaros.