The Clarets were third at the start of the day and Kightly's 65th-minute strike at Turf Moor, along with results around them, ensured they took the second-tier lead once more.
Barnsley, who are looking for a successor to David Flitcroft, almost stole a point when Tomasz Cywka stepped up to take a free-kick but goalkeeper Tom Heaton produced a fine save to keep Burnley in front.
An entertaining first half at Turf Moor ended goalless. Both sides created numerous chances, though arguably the best was fluffed by Clarets striker Sam Vokes inside the opening two minutes.
He latched on to skipper Jason Shackell's long ball forward before firing a disappointing shot straight at grateful Tykes keeper Jack Butland.
Sixty seconds later Vokes went close again, but this time he volleyed inches over the top after pouncing on a poor defensive clearance from the visitors.
Barnsley finally came alive with former Celtic winger Paddy McCourt lifting a shot narrowly over while at the other end David Jones fired in a drive, which Butland was happy to palm to safety.
The Tykes grew into the game and they came mighty close in the 20th minute when striker Marcus Tudgay played a perfectly-weighted through-ball to Cywka.
The Polish winger saw his low shot saved by the legs of Heaton who was also called upon shortly after to save a curling free-kick from Tykes left-back Tom Kennedy.
The final chance of the first period fell to the hosts when Scott Arfield found space, only to lash a shot inches over the top.
Danny Ings had impressed after returning to the Clarets' line-up after injury, and he almost broke the deadlock shortly after the restart when his acrobatic overhead kick only just cleared the crossbar.
However, with the hosts now firmly on top after a purposeful start to the second period, they stormed into the lead after 65 minutes.
Former Tyke Kieran Trippier played a neat pass to the recalled Kightly and he drove a shot confidently past Butland and into the roof of the net from 16 yards.
It had been the least Burnley deserved following their spell of dominance, though Barnsley almost levelled in some style in the 73rd minute.
Cywka cracked in a free-kick from all of 35 yards that appeared destined for the top corner, only for Heaton to produce a smart fingertip save.
As the minutes ticked away the hosts appeared content to hang on to their lead, though Arfield almost doubled the lead after a sparkling, mazy run.
As he bore down on goal he was eventually thwarted by the legs of advancing keeper Butland as Burnley closed out the victory.