Wakefield's unbeaten start to the season came to a shuddering halt, despite having Saints on the ropes in the first half.
A brilliant solo try from Kyle Eastmond early in the second was the key for Saints as they edged out opponents who had often had them worried.
Wakefield had plenty of opportunity in the first 15 minutes to show the resilience that has become their club's middle name. Their fallible handling gave up the ball regularly, but their resolute tackling compensated.
They then showed the attacking panache that has been the other side of their success this season with two tries in two minutes.
Danny Brough sparked the first by running the ball on the last tackle and Glenn Morrison's finger-tipped flick opened the way for Dale Morton to score in the corner.
Then Sam Obst's chip over the defence caused equal chaos on the left, with Darryl Millard touching down and Brough landing a second difficult conversion.
Morrison was desperately close to extending that lead, before Leon Pryce got his long arms free to put Jonny Lomax in for Saints' first points.
Even then, Wakefield would have finished with an even more handsome half-time lead but for Paul Wellens' tackle on Richard Moore.
An instinctive try from Eastmond changed the the game, his subtle dummy and dash for the corner showing why he is such an exciting talent.
It was the more established presence of Keiron Cunningham that put Saints in front for the first time, a spin and plunge from dummy half bringing him a try on his 500th appearance and first game since his compassionate leave following his mother's death.
The defensive workload was getting to Trinity now, with Francis Meli claiming Saints' fourth try. Still Wakefield would not lie down, with a second try from Millard and a lingering threat right into the last minute that they might yet snatch a draw.
St Helens: Wellens; Lomax, Gidley, Wheeler, Meli; Pryce, Eastmond; Graham, Moore, Fozzard, Puletua, Clough, Roby. Substitutes used: Fa'asavalu, Ashurst, Hargreaves, Cunningham.
Wakefield: Blaymire; Murphy, Millard, Gleeson, Morton; Jeffries, Brough; Tronc, Obst, Korkidas, Morrison, Demetriou, Leo-Latu. Substitutes used: Ferguson, Henderson, Davey, Moore.
Referee: T Alibert (France).