Brighton captain Gordon Greer inspired his team to victory to end a run of nine league games without a win.
Greer's goal in first-half stoppage time was the first they had scored in five hours and 43 minutes of football.
Ryan Harley doubled the advantage when he slotted home a rebound after Craig Mackail-Smith's shot had struck the crossbar.
The win lifts Brighton into the top half of the table and leaves Barnsley without an away win since August.
Barnsley had their chances, notably when David Perkins was denied by the bar.
But Brighton, who topped the table after the first month of the season, deservedly brought an end to their recent slump and climbed back into the top half.
Gus Poyet has staunchly stuck to his philosophy of passing football despite results going against them, and he certainly had the game's one genuine class act pulling the strings at left-back.
Unfortunately for Brighton, Mauricio Taricco is 38, the club's assistant manager and has already retired from playing once this season, only to be coaxed back due to a spate of injuries.
To Barnsley's credit they continued to attack, but Greer cleared Ricardo Vaz Te's effort off line, Harper saved from Butterfield and the tireless Taricco blocked Matty Done's shot as the hosts held out.