The scoreline and performance may not have been as convincing almost 46 years on, but the three points were just as welcome and could well be a turning point in Hammers' season as they bid to win promotion to the top flight once again.
It may not have been the prettiest of spectacles and certainly didn't scale the heights of last week's terrific FA Cup fourth round victory at Wolves, but that won't bother Alan Pardew as he reflects on only his third win at Upton Park since taking over as manager last October.
Goals either side of the break from Brian Deane and Christian Dailly sandwiched a freak own-goal from Tomas Repka and a period of play in which Hammers struggled to stamp their authority on the game, but it would certainly have been an injustice had the hosts taken anything less than all three points after dominating possession all afternoon.
Following the cup triumph at Molineux, Pardew was handed a selection dilemma as the cup-tied trio of Nigel Reo-Coker, Adam Nowland and Andy Melville became available, while Tomas Repka returned from illness and veteran Rob Lee declared himself fit again after a three-month lay-off.
In the end, the Hammers boss made just two changes to his starting line-up, recalling Repka to the centre of defence and handing a full debut to new-boy Reo-Coker, as Anton Ferdinand and Kevin Horlock dropped to the subs bench alongside Melville and Nowland.
That meant another outing together for the front pairing of Deane and David Connolly after their impressive display up at Wolves, and the duo both had chances to continue their goalscoring form in the early stages as Hammers began the afternoon in determined mood.
As early as the second minute, Deane found himself in space at the far post after Dailly had flicked on a corner, but the striker saw both his initial shot and the follow-up charged down by defenders.
Six minutes later, Rotherham were opened up again, this time by the guile and invention of Connolly, who played a clever one-two with Brian Deane and raced into the penalty area but saw his point-blank effort well held by goalkeeper Michael Pollitt.
The hosts were clearly in the driving seat, though, and on the quarter-hour mark, it was no real surprise when they opened the scoring. Michael Carrick's floated corner from the right found Deane unmarked 10 yards out and the veteran striker powered a header into the far corner of the net.
With the first goal under their belts and confidence flowing through the side, Hammers surely weren't going to press the self-destruct button again…were they?
Just seven minutes after taking the lead, the back of the net was bulging again, but sadly at the other end. Striker Darren Byfield was allowed too much time and space wide on the right and delivered a deep cross that found Richard Barker pulling away from his marker Hayden Mullins.
The Millers midfielder launched himself into a diving header that Stephen Bywater managed to get a diving hand to. However, with the ball rolling towards the goal-line and the Hammers keeper grounded, Repka failed to get enough of his boot round the ball to clear and only succeeded in finding the back of his own net.
Once again, Hammers were facing the depressing possibility of throwing away yet another seemingly unassailable lead and the fact that the home side didn't manage to register another serious effort on goal before the break only added to the frustrations of the 34,483 Boleyn Ground faithful.
Sedgewick's dipping volley that landed on the top of Bywater's net at the beginning of the second half suggested that things might get worse before they got better but there was a strong sense that Rotherham were there for the taking if Hammers could find their cutting edge again.
With Reo-Coker impressing on his first appearance in a West Ham shirt, Michael Carrick enjoying plentiful possession and Matthew Etherington's pace again striking fear into the opposition, the midfield battle never looked like swinging in Rotherham's favour and provided a strong platform for the hosts to push forward again.
Marlon Harewood almost found the breakthrough in the 57th minute when his firm header from Etherington's looping cross was saved well down at his post by Pollitt, but Hammers fans didn't have to wait much longer for the vital moment.
Two minutes later, another pre-planned corner caused panic in the Millers defence, as this time Etherington drove the ball in and captain Dailly arrived late to send a diving header into the net from 12 yards out for his second goal of the season.
This time, there looked to be no way back for the Yorkshiremen. With Hammers' back four looking more and more assured as the game wore on, it looked as though Pardew's men were on course for a third straight three-goal tally.
Etherington should have scored when sent clear by a delightful pass from Carrick, while Reo-Coker saw Pollitt deny him with a smart save and then went even closer to a debut strike when he skipped on to a through-ball and clipped the ball over the diving keeper, only to see it rebound off the post and bounce past the frustrated Deane as he followed in.
Pardew handed out another debut in the 70th minute when he replaced Harewood with Nowland, who showed some neat touches in an attacking midfield role, while Andy Melville also made his first appearance as a late substitute for Deane in order to make sure there would be no late turnaround for Rotherham.
With a virtually entire new team still getting to know each other, it's perhaps not surprising that Hammers provided a slightly stuttering and stop-start performance, but the winning mentality that Alan Pardew has tried so hard to instil in his players at last seems to be rising to the surface.
Despite this being only their sixth home victory of the season, Hammers are poised nicely in seventh place and, with Jermain Defoe set to make a third comeback from suspension at Bradford next week, it would take a brave man to bet against Pardew's new-look outfit fulfilling their renewed promise.
By Danny Francis