Defender John Fitzgerald and striker Andy Bishop netted their second goals of the season to earn Bury their first victory of the new campaign.
For Sunderland, hoping to name a new manager by early next week, it was a fifth straight defeat and they only had themselves to blame.
Spanish midfielder Arnau Riera, making his full debut for the Black Cats, was sent off after just three minutes. The former Barcelona B team skipper was shown red by referee Michael Jones for elbowing defender Chris Brass.
Bury created the better chances against the 10 men and should have taken a 16th minute lead. Veteran centre-half Kenny Cunningham was guilty of a poor back-pass but youngster Nicky Adams couldn't steer the ball home after nipping in for an interception.
David Buchanan placed a shot on top of the net before half-time while Sunderland went close through their liveliest player, Stephen Elliott.
Bury continued to press for the breakthrough and Fitzgerald and Adams both saw efforts blocked by the busy Black Cats defence.
Little was seen of the visitors as an attacking force until the final 20 minutes. They forced three corners in quick succession while substitute Danny Collins blazed a close-range shot wide of the target.
It proved to be their last opportunity. Brian Barry-Murphy's firs touch after coming on as substitute was to swing in a corner that Fitzgerald glanced home. Unfortunately for the Irishman he jumped into the home fans to celebrate and collected a second booking.
Although down to 10 men themselves Bury held on comfortably and wrapped up their first home win over Sunderland for 44 years when Bishop beat the offside trap to steer the ball past Ben Alnwick.