A double from Marc Bridge-Wilkinson and a strike by winger Cleveland Taylor were no more than the home side deserved for a classy attacking display.
Brighton pulled a goal back with a Matt Richards free-kick with 25 minutes remaining, but they never looked likely to deny the Cumbrians their first win since September 6.
In the 31st minute, Bridge-Wilkinson gave the home side the lead when he neatly turned the ball home from close range from Graham Kavanagh's low cross.
Carlisle extended their lead in first-half stoppage time when Danny Graham cut the ball back for Taylor to steer the ball home from six yards.
It was no surprise when they went 3-0 ahead after 55 minutes when Bridge-Wilkinson rifled the ball into the roof of the net from 12 yards to ensure Richards' goal was no more than consolation.