The big defender headed home early in the second half as victory at Pride Park for the third successive season saw the Tigers climb up to second place in the table ahead of Saturday's fixtures.
Robert Koren put the visitors in front but Michael Jacobs levelled things up on the stroke of half-time.
It could be argued that it was against the run of play when the visitors went ahead. Robbie Brady crossed from the left and his dangerous ball across the six-yard line was swept home by the left-foot of Koren.
Craig Bryson had Derby's first shot in anger immediately afterwards, with goalkeeper Eldin Jakupovic doing well to hold a 25-yard effort that bobbled in front of him.
A half-time deficit would have been harsh on Derby and Jacobs ensured there was no such injustice with a superb equaliser in first-half injury time.
Jacobs' curling cross had to be pushed over by Jakupovic and when Faye could only head Paul Coutts' resulting corner as far as the edge of the area, Jacobs controlled the ball and volleyed a right-foot shot into the bottom corner of the net.
However, Faye made amends five minutes into the second half when he headed home unmarked from close range following a Brady corner.
Jakupovic did well to gather Jacobs' deflected shot from a free-kick just outside the area after an hour and the Swiss stopper shone again midway through the second half, pushing Paul Coutts' effort out for a corner.
Hull had to defend numerous balls into their box late on but they were up to the challenge and finished the night in an automatic promotion spot.