Leeds overcame bitter Yorkshire rivals Bradford in a hard-fought Grand Final at Old Trafford to end their 32-year wait for a league championship.
The Rhinos went into the game as slight underdogs but led 10-4 at half-time thanks to a Matt Diskin try and six points from the boot of Kevin Sinfield.
Bradford's Shontayne Hape touched down at the start of the second half to reduce the deficit to two points.
But Danny McGuire's try five minutes from time sealed victory for Leeds.
The Rhinos drew first blood when Sinfield kicked a penalty after Joe Vagana was punished for pinching the ball in the tackle.
But Bradford scored the first try of the game, a slick passing move eventually ending with Lesley Vainikolo going over in the left corner on eight minutes.
Both sides were tackling hard, refusing to give an inch.
And the physical confrontation took its toll on Bradford's Vagana, who was forced to leave the field midway through the first half with a shoulder injury.
The Rhinos went back in front when Diskin squeezed his way through the Bulls defence on 15 minutes, the try converted by Sinfield.
And, after Hape's try had been ruled out by the video referee, the lead was up to six points when Sinfield kicked another two points to put his side 10-4 up at the break.
Bradford struck right at the start of the second half when Hape went over to reduce the deficit to just two points.
But Bradford's cause was not helped by the loss of full-back Michael Withers with a leg injury.
Even with Withers, the Bulls would have struggled to break down a resolute Rhinos team.
And when McGuire jinked his way to the line five minutes from time after swapping passes with Keith Senior, the writing was on the wall for Bradford.
Sinfield's conversion made it an eight-point gap - and the Leeds fans began to celebrate a famous win.
Bradford: Withers, Reardon, Johnson, Hape, Vainikolo, Harris, Deacon, Vagana, Paul, Fielden, Peacock, Swann, Radford. Replacements: Pratt, Langley, Parker, Anderson.
Leeds: Mathers, Calderwood, Walker, Senior, Bai, Sinfield, McGuire, Ward, Diskin, Bailey, McKenna, Lauitiiti, Furner. Replacements: Burrow, Poching, McDermott, Jones-Buchanan.
Referee: Steve Ganson (St Helens).