Mr Ahern was premier from December 1987 to September 1989 after a prominent stint under Mr Bjelke-Petersen, who resigned amid the damage from revelations from the probe into police corruption.
Mr Bjelke-Petersen had seized control of politics in Queensland for much of 1987, serving as both premier and treasurer.
Almost all the levers of power rested in his office, and he reserved access to department briefings to his inner circle of trusted ministers.
Tensions boiled over in November when he effectively stopped speaking to most of his executive team and wrote to governor Walter Campbell, requesting he sack a quarter of his ministers, which the governor refused.
The premier was eventually successful in getting three ministers sacked, including his successor Mr Ahern.
Victory would be short-lived.
Mr Ahern took leadership of the National Party days later, and Mr Bjelke-Petersen resigned as premier on December 1.
As the new leader, Mr Ahern famously declared he would implement the findings of the damning Fitzgerald findings "lock, stock and barrel".
His death was confirmed on Friday morning in a statement issued on behalf of the family by federal Nationals leader David Littleproud.
"The National Party family has lost one of its greatest today," Mr Littleproud said.
"Mike Ahern and my father are two of the greatest influences on me and my pursuit of politics."
Mr Littleproud, whose father Brian was a backbencher in the Bjelke-Petersen years and later a minister, said he still wore the tie and cufflinks gifted to him by the former premier.
"It's difficult to describe all that Mike Ahern achieved and stood for, but integrity is what Mike Ahern embodied in all that he did during his time in public office," Mr Littleproud said.
"We are a better state and country for having Mike Ahern and our National Party family's thoughts are with Andrea and the family during this sad time."
Queensland Liberal National leader David Crisafulli said the state had lost a giant who always put people ahead of politics.
"Mike Ahern let the sun shine in on government in Queensland more than three decades ago," he posted on social media.
"The decisions he made back then still resonate with Queenslanders today."
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