Rory O'Gorman pleaded guilty in June to drug possession and dealing with the proceeds of crime after police found 7.5 kilograms of the drug and about $120,000 in cash at his Bondi Junction apartment.

A sentencing hearing at the Sydney District Court heard that O'Gorman began smoking cannabis heavily following a football accident at the age of 18, in which he broke his back.

His sister, Kilty O'Gorman, told the court he began "self-medicating" to deal with the pain of the injury and the emotional impact of being struck down with such a catastrophic injury in his prime.

He had been making a recovery and was studying at Sydney University when about five years later, in 2003, he was bashed by security guards at a university function and "left for dead", Ms O'Gorman said.

"I think that was the most traumatic experience that Rory has had in his life," she told the court.

She was aware he had been smoking marijuana but was "deeply shocked" when he was arrested for supplying it.

O'Gorman's barrister, Philip Boulten, SC, said his client was no longer smoking cannabis and had become a new father in the past week.

He told the court his client had the strong support of his family.

"A very significant member of his family is in court today," he said.

Ms Rhiannon did not give evidence in the sentence hearing.

The matter was adjourned to September 10.

Ms Rhiannon was a Greens MP in the NSW upper house.

She resigned to run on the Greens NSW ticket for the Senate in this month's federal election.

Counting is continuing, but she is widely tipped to win a Senate seat for the Greens in NSW.