Tyler Silsby’s second-half goal gave them a 1-0 win over Manchester United in the PL2 play-off final.
It was an advantage they preserved heroically as United piled men forward and plied their biggest threat Shea Lacey with possession in the closing stages.
In the end, the hosts arguably deserved their win after showing two very different sides of their game.
They zipped the ball about with confidence in a free-flowing first half.
Harry Howell forced United goalkeeper Will Murdock into a smart grab inside three minutes.
But Daniel Gore, who played 41 games on loan at Rotherham this season, sent a good chance over for United from a rapid counter-raid.
Albion wingers Silsby and Miah Oriola quickly showed they could beat their full-backs but the end product was a little wayward.
Not least when Silsby blazed wide on 25 minutes after brilliant work by Shane Nti to send him through.
Albion should have gone ahead on the half-hour. They won possession high up and Oriola, having drifted infield, released Josh Robertson outside him.
But the midfielder shot straight at Murdock.
Howell fizzed a shot narrowly over after being picked out by a clever pass from centre-back Noel Atom.
The Albion defender missed a straightforward through ball late in the half but got back well to block the resulting shot by Victor Musa.
And Nti sent a great chance wide soon after when a short back pass sent him racing clear.
Seb Jensen made a decent save diving to his right to parry from Lacey right at the end of the half but the fear at the interval was that Albion had missed their opportunity.
As it was, they went ahead in the 58th minute with both their dangerous wingers involved.
Silsby was the scorer at the far post after Oriola had released Sean Keogh, whose low cross was allowed to travel a long way.
Albion sub Zane Albarus almost added insurance when his volley flew narrowly wide.
But mainly it was about digging in and defending.
United’s response was all about the trickery of Lacey, who looked to create space for others and also chipped a cross on to the roof of the net.
Jensen stretched to tip over Jack Fletcher’s header and Atom and Ben Barclay both put in crucial challenges in front of goal.
And then, after eight tense minutes of stoppage time, it was all about celebration.
Albion, not United or Manchester City or Arsenal, are Premier League champions.
Albion: Jensen; Mackley, Barclay, Atom, Keogh (West 75); Middleton (Albarus 61), Robertson; Silsby, Howell (Shaw 75), Oriola; Nti. Unused subs: L.Ferdinand, Belmont.