Jimmy Sullivan, 44, was the independent MP for the Queensland electorate of Stafford in Brisbane's north.
Police were called to Mr Sullivan's Stafford home unit about 10.15pm on Thursday where they found his body.
The death is not being treated as suspicious and a report will be prepared for the coroner.
Mr Sullivan was elected to parliament as a Labor MP in 2020 and served as Minister for Justice and Veterans Affairs assistant under former premier Steven Miles.
He was a long-serving chief of staff to former attorney-general Yvette D'Ath.
He was re-elected in the 2024 state election, surviving a 5.5 per cent swing against him as the Miles government was swept from power by the David Crisafulli-led Liberal National Party.
He fell out with Labor soon afterwards, with police called to an alleged domestic incident at his home the day after the election.
No charges were ever laid.
He was placed on leave to attend to medical and legal issues, before being disendorsed by Labor in May 2025, forcing him to the crossbench.
Speaking as an independent in parliament for the first time, Mr Sullivan broke down, telling MPs he was suffering from post-traumatic stress disorder caused by the death of his first daughter.
"I spiralled, I recognise that, and I put my hand up for healthcare," he told parliament.
Opposition Leader Mr Miles accused him of failing to adhere to a "safe return to work plan".
He was the son of former Labor MP Terry Sullivan, who also served the Stafford electorate from 2001 to 2006.
On his parliamentary web page, Mr Sullivan described himself as "a local through and through" who had grown up and gone to school in the electorate.
Before politics, he was a lawyer and former judge's associate in the District Court of Queensland.
He worked across government and law reform in Canberra, Brisbane and Washington DC, working in the office of Democratic Senator Ron Wyden.
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