Christopher James Finn, an ex-commando who served in Afghanistan, applied for bail in Queensland Supreme Court on Wednesday.
Finn's solicitor Andrew Owens told Justice Paul Smith his client had been doing well on parole until a personal tragedy caused a drug relapse.
"He joined up with other veterans, who were also exposed to the criminal justice system, for support," Mr Owens said.
"One of those group members passed away and that seemed too much for Mr Finn, who relapsed."
Finn was jailed for four years in March 2023 after pleading guilty to a total of 38 mostly drug-related charges.
He committed the offences during a 14-month crime spree that ended when he was found in possession of a loaded revolver in public in August 2022.
Justice Smith heard Finn was released on parole in January this year and months later attended a residential unit when it was raided by police.
Mr Owens said Finn was not named on the search warrant and denied ownership of the nearly 45 grams of methamphetamines police alleged was found at the unit.
"He was in the process of relapsing. It was a chance thing. He intended to buy drugs for a party. He was struggling with mental health," Mr Owens said.
Police allegedly found evidence on Finn's phone of him supplying Viagra.
A later search of his home also allegedly uncovered a disassembled firearm, knuckle dusters, unlawful medication and records of drug debts.
The court previously was told Finn served in the army for 10 years and was diagnosed with PTSD after witnessing "significant traumatic events" during four tours.
Finn's life began "spiralling downhill" in August 2020 when he turned to drugs as his mental health deteriorated, his previous barrister said.
Mr Owens asked Justice Smith to extend the court's leniency.
"He's a man who despite his service to his country and his significant issues, he has had chances, I can't get around that," he said.
"But what we seem to know is he is a motivated individual ... he was engaging with veteran-specific community service."
Justice Smith refused Finn's bail application.
"I have read about his history. It's a sad case," Justice Smith said.
"I think there is an unacceptable risk of committing offences while on bail."
Justice Smith said there had been no guarantee the parole authorities would have allowed Finn leave custody if bail had been granted.
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