Hawley's fantastic second half strike came against the run of play and gave the Cumbrians the two goal cushion they were after.
Raphael Nade had given Carlisle an early lead with a sublime volley from Derek Holmes' cross.
The Ivory Coast winner latched on to Holmes' inviting near post cross and caressed the ball in front of Billy Turley and inside the far post.
Nade had obviously been paying attention - just 90 seconds earlier Chris Lumsdon's almost identical shot had forced a great save from Turley.
Oxford should have been level five minutes later when Danny Livesey appeared to foul Steve Basham but Cumbrian referee Mike Pike failed to point to the spot.
Livesey was then lucky not to be booked when he seemed to want to swap shirts early after an another exchange with Basham.
The U's came out fighting in the second half but despite their pressure - typified by Chris Hackett's performance - chances were hard to come by and their lack of firepower was highlighted by Carlisle's second goal.
Peter Murphy's free kick was flicked on by Holmes and with his back to goal Hawley allowed the ball to drop to his feet and in one movement turned on a sixpence past his marker to fire home from 6 yards.
The goal, Hawley's 13th of the season, put Carlisle in control and when they introduced new loan signing Michael Bridges into the action, a landslide seemed on the cards.
But despite the ex-Sunderland and Leeds striker having some nice touches further chances eluded the Cumbrians before Oxford's late comeback.
Hackett, a thorn in Carlisle's side all game, made yet another telling run and passed to Lee Bradbury and the former Premiership striker stroked a left foot shot past Keiren Westwood from 20 yards.
With just injury time remaining Oxford piled on the pressure but Carlisle stood firm to take another three points.