Charlie Cameron (four goals) and Will Ashcroft (32 disposals) starred when it mattered most in the Lions' 18.14 (122) to 11.9 (75) victory in front of 100,022 fans on Saturday at the MCG.
Father-son product Ashcroft was awarded the Norm Smith Medal as best afield in the season decider for the second straight year.
Co-captain Harris Andrews and Dayne Zorko were brilliant in defence, as Brisbane rubber-stamped themselves as the most successful club this century with a fifth flag.
Geelong and Hawthorn have four each.
The Lions' latest success could be the making of a dominant period under Chris Fagan, similar to the Leigh Matthews-led premiership juggernaut of 2001-03.
Fagan took over in 2017 when the Lions were at their lowest ebb and has since steered them to three straight grand finals and two flags.
"It's all about the culture," Andrews told Seven.
"We've got a really special group of guys, special staff. We wrap our arms around everyone.
"To see the adversity we've gone through this year and last year as well and to come out the other side, it's phenomenal.
"It's sort of dawning on me a little bit the journey we've been on since Fages got here ... it's awesome."
Nothing split the two best sides in the competition in the first half, with scores locked at the main break for the first time in a grand final since 1909.
Brisbane gun Lachie Neale started as the sub on his early return from a calf injury and was activated for the second half, tallying 17 disposals, seven clearances and one goal.
The two-time Brownlow Medal winner slotted one of three crucial majors late in the third quarter - Cameron kicked the others - as the Lions seized control of a tight contest in the space of six minutes.
Geelong held the lead 18 minutes into the third term, but Brisbane kicked eight of the next nine goals to run away with the flag.
"I'm so proud of this group ... that performance was hard to describe," Neale told Seven.
"When we're on, we're on. At halftime it certainly didn't look like it was going to be a result like that.
"Maybe halfway through the last when we piled on a few, I was like, 'Oh my god, we're going to do it again'."
The Lions played most of the second half a man down after Brandon Starcevich suffered concussion.
Hugh McCluggage (25 touches, four goals) and Jaspa Fletcher (29 touches) shone, and Zac Bailey had 1.6 to his name at one stage but finished with three majors.
Geelong speedster Max Holmes (33 disposals) and Ollie Dempsey (four goals) fought all day for the losing side.
Coleman Medal winner Jeremy Cameron was held goalless by Darcy Gardiner and struggled with a right arm injury after he was hurt under friendly fire from Cats captain Patrick Dangerfield.
It was Geelong's second loss from four grand finals under 15-year coach Chris Scott, and a third in seven deciders this century.
"To our guys, be proud and hold your heads up high," Dangerfield said.
"We don't as Australians always celebrate those that come second all that well, but there's plenty to be proud of today.
"Beaten by a better side, but very proud of our team."
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