McCluggage rejected overtures from several rival clubs to commit to the Lions until the end of the 2031 season.
"I still feel as though we have unfinished business," the 26-year-old said on Tuesday.
"I love how far we have come since Fages (coach Chris Fagan) got here, and the attitude that we have towards consistently getting better as players and people.
"We have had so many great experiences to learn from and use to get to where we want to be.
"The challenge now is to remain a good club and football team long into the future like the best clubs in the competition are able to do."
The Warrnambool, Victoria, product has played 166 AFL games for Brisbane since being recruited with pick three at the 2016 draft - the same time Fagan  took over as coach.
McCluggage has been a key plank in Fagan's rebuild of the Lions, who have played finals in the past five seasons and were beaten by Collingwood in last year's premiership decider.
A spate of injuries has hampered Brisbane this season - they are 13th on the ladder with just four wins - but McCluggage forecast a bright future.
"I am excited to see what we can do with the current list we have," he said.
"Individually, I just want to be the best teammate I can ... as a team we need to remain consistent and continue to provide a hard working but fun environment for everyone who comes through our club to thrive.
"If we do that, I have no doubt that on-field success will follow."
Brisbane's football manager Danny Daly said re-signing McCluggage, who was due to reach free agency status at the end of the season, was a coup.
"We couldn't be happier ... Hugh is an outstanding player and more importantly he is an exceptional person who epitomises everything we stand for as a football club," Daly said.
"There's no doubting the club is where it is because of having Hugh help drive the standards and build the culture we have here.
"He is a fantastic leader who has been our vice-captain for several seasons and he has all the traits to one day be the captain."
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