The striker registered his 11th goal of the season moments after Issa Diop had given the hosts the lead.
This weekend marks 10 years since Sullivan and Gold bought West Ham, and the controversial duo admitted in their programme notes that the club have not progressed on the pitch as much as they had hoped in that time.
It was hard to argue against that sentiment as West Ham were 17th when they took over, and a decade on they kicked off against Everton in precisely the same position.
In fact, “10 years of failure” was the verdict of the hundreds of disenchanted fans who gathered outside the stadium to protest against the owners before the match.
Yet things were looking brighter inside the ground, at least for the majority of the first half, against an Everton side still finding their feet under Carlo Ancelotti.
Hammers boss David Moyes, facing his old club, had called for his players to give record signing Sebastien Haller more service and Mark Noble did just that, standing up an early cross which the French striker headed narrowly wide.
Snodgrass had the ball in the net after bursting clear only to be pulled up for offside before Noble again played in Haller, whose angled drive was blocked by the legs of Jordan Pickford.
The goal West Ham had been threatening arrived five minutes before the interval, Snodgrass whipping in a free-kick and Diop glancing in a header.
But Everton hit back immediately, also from a set-piece, when Mason Holgate flicked on a corner for Calvert-Lewin to convert at the far post.
There was still time for Haller to meet Zabaleta’s cross only to be denied by a point-blank save from Pickford before the break.
Pickford almost dropped a clanger early in the second half when he spilled a high ball but Holgate bailed him out by collecting Haller’s prod at goal.
The England keeper just about held on to another Haller header and clawed a deflected Snodgrass header wide as West Ham pushed for a winner.
The Hammers were left frustrated, though, and sub Albian Ajeti survived a late VAR check for a possible red card after planting the back of his head into Holgate’s face.