The Seagulls pulled off a surprise victory despite playing for the final hour with only ten men.
Defender-turned-striker Adam Virgo was sent off by referee Dermot Gallagher for a second-bookable offence.
Virgo was cautioned after just four minutes for clattering into Stephen Caldwell and received a second yellow card for a foul on Jeff Whitley.
Brighton were already a goal up by then - Richard Carpenter scoring with a deflected drive in the 26th minute after a cross from Paul Reid was headed clear by the Sunderland defence.
The Seagulls defied their numerical disadvantage to double their lead in the 43rd minute. Carpenter's corner - Albion's first of the game - was headed in from eight yards by the unmarked Mark McCammon, for his third goal in two home games.
Sunderland manager Mick McCarthy made a double substitution for the second half, bringing on Sean Thornton for Whitley and Chris Brown as an extra striker at the expense of Dean Whitehead.
The changes almost paid off when Thornton saw a snap-shot fisted clear by Rami Shaaban, making his debut in the Brighton goal.
The former Arsenal shot-stopper, signed on a non-contract basis, also saved a shot from an Argentinian winger Julio Arca midway through the second half.
Arca reduced Sunderland's arrears ten minutes from time with a low drive from the edge of the area, before Thornton hit a post from 25 yards in a frantic finish.