The veteran hit-man, who turned 39 last Monday, notched his sixth goal of the season by diving to head home Calvin Andrew's deep left-wing cross in the 57th minute.
It gave Town a share of the spoils after a simply awful first-half display which left Luton lucky to be just one goal down at the break.
That came in the 26th minute when James Hayter headed in James Coppinger's cross from the right.
And Rovers could have had more goals as Luton, with Chris Coyne off injured, struggled to cope with the visitors' one-touch football.
In the end Town did enough for the draw, but it couldn't stop the boos echoing out of the stands as the players left the field.
The Hatters showed just one change to the side that picked up a first away point of the season in Tuesday night's 0-0 draw at Yeovil as Furlong returned from a one-match ban in place of the injured David Bell.
Doncaster showed two alterations to the side that lost 3-2 at home to Walsall in midweek as Coppinger and Stephen Roberts replaced the injured Paul Heffernan and suspended Lewis Guy respectively.
Amid a somewhat flat Kenilworth Road atmosphere, the game got off to a slow start before Furlong found space on the left eight minutes in and sent in a cross which just evaded Darren Currie at the far post.
A minute later Luton almost got in again when Furlong this time picked out Andrew in space inside the left-hand side of the penalty area.
The striker looked like he could have gone for goal, but instead pulled the ball back for the onrushing Dave Edwards, whose shot was blocked into the path of Alan Goodall, who blasted the rebound over from 20 yards.
Rovers responded in the tenth minute as a Brian Stock corner was cleared only as far as Roberts, who flashed a volley just over from the edge of the area.
As Luton began to lose their way the visitors began to boss possession with some neat interplay in the middle of the park.
In the 18th minute Doncaster spurned a great opportunity when Edwards' misplaced pass allowed Coppinger a clear run at the defence, but with Hayter in acres of space alongside him, Coppinger tried to go it alone and saw his effort blocked.
The Hatters' desperation was shown by Currie being booked for a wild lunge on Stock in the 23rd minute and three minutes later Town were behind.
The lively Coppinger got away from Goodall on the right and crossed for the unmarked Hayter to easily nod home from six yards.
Spring hit a 25-yard left-foot effort at Neil Sullivan in the 28th minute, but four minutes later things got worse for Town as Chris Coyne limped off to be replaced by Richard Jackson.
Hatters then capitulated as Mark Wilson went close three times in the space of five minutes volleying just wide from 20 yards in the 34th minute, hitting a cross-shot past the post three minutes later and then firing over after a one-two with Hayter in the 39th minute.
Luton were ragged and had an amazing let-off in the 41st minute as another Stock corner caused chaos in the box as Coppinger had a shot blocked, then Hayter hit the inside of the post from close range before Roberts put the follow-up header against the bar.
Town did at least rally with Furlong and Edwards heading just off target before the break, but Hatters trooped off at half-time with chants of "Blackwell sort it out" ringing around the stadium.
Luton couldn't get any worse in the second half and they stepped up their game and threatened when Goodall hit a left-foot, 25-yard effort wide in the 55th minute.
Two minutes later they were level as Andrew, who was coming back on to the pitch after receiving treatment for a head injury, picked up the ball from Robinson wide on the left and sent in a deep cross that was headed home by the diving Furlong inside the six-yard box.
Richie Wellens forced Ben Alnwick into a save at his near post on a rare Rovers second-half attack in the 63rd minute before Furlong could only guide the ball into the arms of Sullivan in the 75th minute after Andrew had headed down a Goodall cross.
But that was the best both sides could muster as the game petered out into a drab draw.