McCulloch netted two penalties and then added another strike from open play in the first 45 minutes of the match against Airdrieonians at Ibrox.
It was his third hat-trick of the season; he had scored three goals in consecutive weeks against East Fife and Arbroath back in August and September. And the 35-year-old, who has played the vast majority of the 2013/14 campaign at centre- half, took his personal tally to 17 with his goals.
But, more importantly for his club, they put them out of reach of nearest rivals Dunfermline, who they take on at home on Saturday, at the top of the division.
Ally McCoist's undefeated charges are now 26 points clear of the second-placed side - and there are only eight games left and 24 points remaining to play for. The comfortable victory, recorded in front of a healthy crowd of 41,343, also helped to put one of the worst performances of their season firmly behind them.
McCoist made one change to the side that had struggled to earn a 1-1 draw and a replay with Albion Rovers in the William Hill Scottish Cup at the weekend. Dean Shiels, who had been out-of-sorts on Sunday, dropped to the bench and Andy Little, who had come on in the second half against Rovers, replaced him.
Little won a penalty in just the second minute of the match when he was fouled by opposition goalkeeper Grant Adam as he chased down a David Templeton chip.
Adam, the former Rangers youth player, was yellow- carded by referee Brian Colvin and designated penalty taker McCulloch stepped forward.
The skipper made no mistake with the spot-kick. He drilled the ball high into the roof of the net, as Adam dived the other way, to put the home team in front.
Jon Daly nearly doubled his side's tally in the 13th minute when he got on the end of a curling Richard Foster cross from wide on the right flank. His effort, though, hit the side netting.
Rangers went further in front in the 21st minute after they had been awarded another penalty by Colvin. Liam Watt brought down Templeton inside his own area.
McCulloch chose to power the ball straight down the middle on this occasion. And, once again, he hit his target to spark the start of the title celebrations.
"Stand up for the champions!" bellowed the members of The Blue Order in the Broomloan Road Stand - and all of their fellow-Rangers supporters inside the stadium duly obliged.
Nicky Law was, like many of the Rangers team, much improved from the Rovers debacle. He got upfield whenever play allowed and forced a fine save from Adam in the 27th minute.
Airdrie have improved dramatically since Gary Bollan took over as manager last year and have moved up the League One table to give themselves a chance of survival. They had certainly given their Glasgow rivals a torrid time when they met them in a bad-tempered league encounter at the Excelsior Stadium in January.
But they offered little resistance last night. The only shot on goal they had in the first half came from Caolan McAleer and it was a speculative long-range effort.
McCulloch completed his hat-trick in the 41st minute after Law had supplied him on the edge of the Airdrie area. He dinked a left-foot shot into the bottom-right corner. Little and Templeton both limped off injured just before half-time and they were replaced by Nicky Clark and Arnold Peralta respectively. It was Clark's first appearance since he had injured a foot in the game against Airdrie in January and he received a warm reception from the Gers support.
The ball broke to McCulloch on the edge of the Airdrie penalty box early in the second half and he shot through a cluster of bodies. Adam did well to block it.
Bilel Mohsni, his fellow centre-half, was clearly keen to get in on the goals, too. The French-Tunisian struck the inside of the post with a shot shortly after.
Full credit to the visitors, they kept on fighting and James Lister had a shot well saved by Cammy Bell in the Rangers goal on the hour mark.
The game fizzled out after that. But the Rangers supporters were still in good voice as their heroes finally completed Stage Two of what has become known as "The Journey".
What lies ahead in the summer and beyond, with continuing friction between the club hierarchy and the fans and financial cutbacks expected, is anybody's guess.
But the Gers fans, who have been through so much in the last few years, put their worries to one side and enjoyed their evening and then some.
They celebrated heartily as another significant milestone on the road back to the forefront of Scottish football was reached.