United's run became one defeat in 12 games but it ultimately wasn't enough to keep their play-off dreams alive despite giving it everything they had in what was a very good game to watch.
The hosts kept the ball well from the kick off as they probed the left flank with Grainger, Campbell-Ryce and Jones right at the heart of it. It eventually led to an opening for Jones, from distance, but Shea stepped across to deal with his drilled effort.
United used the same avenue of approach to good effect when Campbell-Ryce and Grainger combined to put Devitt into acres of space. Shea had more to do as he was forced to parry a curling dipper.
Luton started to settle and Olly Lee should have done better as he arrived late on the edge of the box. His attempt at cushioned control on his chest went wrong and the ball bobbled harmlessly behind.
United were awarded a penalty on 12 minutes when Nadesan dinked the ball through legs inside the area for Bennett to chase. Shea raced off his line and went for the block, and the referee had no hesitation in pointing to the spot as the big striker tumbled to the floor. Captain Danny Grainger placed it and he made no mistake as he sent the stopper the wrong way.
The home side came again when Joyce went past his man and crossed low. The ball ran unhindered across the face of goal and was eventually put behind for a corner as Campbell-Ryce worked hard to keep the pressure on. Devitt sent his set piece to the back stick and Hill was disappointed to see his header fly straight at Shea.
Another good corner routine brought another measured header from Hill as he pulled off his man to make room for a nod down. Bennett was onto it, but his touch came off a shoulder and it was easy for Shea to grab.
Luton enjoyed a better spell just before the half hour but Stacey had a shot blocked, as did Olly Lee, and the blue ranks closed tight to protect their goal.
Hearts were in mouths as Olly Lee skipped past the back line but Bonham spread himself to take the sting out of the goal bound cross. Ellis completed the clearance before the ball could trouble the target.
A 30-yard free kick from Devitt dipped a moment too late as he tried to find the roof of the net, and Carlisle survived an almighty scramble at the other end when Sheehan dropped an excellent free kick delivery into the mix. Loud shouts for handball were waved away, a header from Hylton was blocked, and Grainger showed great bravery to lunge in to prevent Rea from sending a rasper through the ruck of bodies.
The visitors were first to show after the break when Ruddock found himself unmarked on the edge of the box. He took time to get the ball where he wanted it before sweeping a left footed volley just past the post.
A wicked Grainger free kick on the hour needed just a touch from any of the five advancing home shirts as it angled towards Shea, but the keeper was able to pull it into his midriff as players threw themselves down in an attempt to finish it off.
An even better chance followed when Campbell-Ryce twisted his way expertly past his marker. It seemed to be perfect for Bennett but he took his eye off the ball and it ricocheted away to safety off his shoulder.
Carlisle were made to pay for the miss almost immediately as a lightning quick break brought a shot from Hylton which Bonham could only parry. Olly Lee kept his cool and calmly slotted the loose pieces into the back of the net.
United pushed men forward but they were almost caught on the break when Ruddock somehow bundled his way through three challenges to leave himself with just Bonham to beat. The stopper made the save and the defence was able to recover.
The hosts had a great chance of their own with eight minutes left to play when Bennett wrapped the ball to Devitt just 16-yards from the target. His first touch was perfect and Shea was rooted to the spot and mightily relieved to see the ball whisk past his post as the winger pulled the trigger.
Ruddock missed a late chance to clinch all three points when he nodded a Lee cross into the grass, and then headed the rebound onto the top of the bar.
Twardek glanced a late, late header from a Grainger corner over the bar, and that was that as the final whistle blew.
Carlisle United - Grainger (13 pen)
Luton Town - O Lee (63)
Carlisle United - Ellis (44), Grainger (76), Jones (90)
Luton Town - Potts (44)
Carlisle United - Bonham, Brown (Miller 72), Ellis, Hill, Grainger, Devitt, Joyce, Jones, Campbell-Ryce (O'Sullivan 63), Bennett, Nadesan (Twardek 72). Subs - Gray, Parkes, Lambe, Stockton.
Luton Town - Shea, Potts, McCormack (Mullins 90), Stacey, O Lee, Hylton, Rea, Ruddock-Mpanzu, Collins, E Lee (Downes 90), Sheehan. Subs - Stech, Justin, Cornick, Jervis, Gambin.
Referee - Seb Stockbridge
Attendance - 5,523 (1,404 away fans)