Northern Ireland international winger Brunt made in four goals in three games with Albion's second in the 59th minute as Tony Mowbray's rock-bottom side ended a run of 11 Premier League games without a win going back to their 3-0 victory against Middlesbrough on January 17.
Central defender Jonas Olsson had given Albion the lead five minutes before half-time as Sunderland, without an away win since December, slipped to a potentially costly defeat.
Albion set the seal on their success in the 88th minute when on-loan Argentinean winger Juan Carlos Menseguez scored his first goal for the club.
Sunderland looked to have got their survival bid back on track in their previous game when they beat Hull City to end a run of four straight defeats.
But they never got into gear against Albion and a punchless display left them right back in the thick of the fight for survival.
Sunderland started liked a side still worried about securing their Premiership status and were never able to raise their game above that level.
Some better finishing from Albion in the opening exchanges would have given them a decisive advantage even before Olsson broke the deadlock.
But Robert Koren saw his shot blocked, Gianni Zuiverloon blazed wide and Brunt was denied by a smart save by the well positioned Marton Fulop who started the game as a replacement for knee injury victim Craig Gordon.
It took Sunderland half an hour to build up any kind of momentum and Carlos Edwards should really have done better when he met an Andy Reid cross at the far post only to see his header loop on to the roof of the net.
Former Albion loanee Kieran Richardson then forced Scott Carson into a stunning one-handed save with a swerving drive from 40 yards.
But that was as good as it got for Sunderland and Albion made a deserved breakthrough in the 40th minute.
Sunderland failed to deal with an in swinging corner from Jonathan Greening and Abdoulaye Meite flicked it on into the path of Olsson.
The giant Swedish central defender was falling back when he made contact with the ball, but his left-foot drive whistled past the outstretched hand of Fulop.
Fulop was equally powerless when Albion doubled their advantage 14 minutes into the second half.
Mark-Antoine Fortune was given far too much time and space on the right-hand edge of the Sunderland area and his pin-point cross was easily converted from close range by the on-rushing Brunt.
Sunderland needed a swift response to try and salvage something from the game - and Djibril Cisse should have given them a lifeline in the 64th minute.
He was only six yards from goal when he tried to deflect Teemu Tainio's 20-yard drive into the net but only succeeded in deflecting the ball over the bar to perfectly sum up Sunderland's dismal day.
Sunderland's misery was completed when Brunt turned provider to cut in from the right wing and roll a pass into the path of Menseguez, who finished neatly with a shot on the turn from 12 yards.