The Scottish champions knew a win would secure the silverware and add to the Co-operative Insurance Cup already secured this term, regardless of events at Celtic Park, and this match was effectively over as a contest after just seven minutes.
Lafferty, who had netted in the last two title deciders, was on target again this time around, helping himself to a hat-trick, with Steven Naismith and Nikica Jelavic also on the scoresheet on the day dubbed Helicopter Sunday.
The win means veteran boss Walter Smith signs off with 10 championships, and a total of 21 trophies, over his two spells at the Ibrox helm, as he now makes way for Ally McCoist to take over the reigns.
Smith named an unchanged side for the fifth time in a row for the visit to Rugby Park, while Kilmarnock were without star man Alexei Eremenko through suspension and drafted Mehdi Taouil into the side as his replacement.
Rangers needed an early goal to settle the nerves and enjoyed the best possible start to the game when they surged ahead with just 47 seconds on the clock.
Steven Davis released Lafferty and he lofted high over the reach of goalkeeper Cammy Bell and into the back of the net from the edge of the box.
The Ibrox side were celebrating again with five minutes gone. This time, Gregg Wylde played the ball to Naismith, who took a touch before lashing home.
The second goal was marred slightly by the sight of a supporter invading the pitch, although he was quickly apprehended by police and stewards.
The goals kept coming and the champions extended their lead further two minutes later when Jelavic set up Lafferty to sidefoot past the helpless Bell and claim his second of the day.
Rangers could have added to their tally when Steven Whittaker raced down the right flank before picking out Naismith and he touched on for Jelavic, but his flick was deflected wide of target.
At the other end, Kilmarnock could have pulled a goal back when James Dayton tried his luck with a shot that goalkeeper Allan McGregor did well to block.
Only the woodwork prevented Walter Smith's men from heading into the interval with a bigger advantage after Davis saw his ferocious strike crash off the post.
McGregor was called into action on the stroke of half-time and was again up to the task, this time denying Craig Bryson.
Rangers' start to the second half was almost as impressive as their explosive opening spell to the game, as they notched up another two goals within eight minutes of the restart.
Jelavic contributed to the goals haul after 49 minutes when he was tripped just outside the area by Manuel Pascali and brushed himself off to send a swerving free-kick into the top corner.
Naismith then embarked on surging run before slotting into the path of Lafferty to stroke home and claim his hat-trick with 53 minutes gone.
Kilmarnock did manage to pull a goal back after 65 minutes when Dayton's free-kick took a deflection off the wall and hit the post before finding the back of the net.
Rangers hit the woodwork again when Naismith's shot bounced off the crossbar, before Lafferty ballooned the rebound over.
The celebrations had already been under way for some time, but the majority of Rugby Park erupted when the final whistle sounded and confirmed that Rangers had retained their SPL crown.