Diego Marques-Santos (33) was sentenced in the Dunedin District Court in April last year to three and a-half years' imprisonment after pleading guilty to four counts of stupefying and five of using a document.
During that period in prison he also spent time in hospital in October after fellow inmate Anthony Wheble slit his throat.
Wheble was later jailed for seven years.
While a deportation order was served on Marques-Santos in November 2017, the Parole Board could only release him when it was "satisfied that the arrangements in Brazil [were] adequate to address risk issues".
At a hearing at the Otago Corrections Facility last month, panel convener Judge David Mather accepted that was now the case.
The board received a letter from Marques-Santos' sister, who offered to help on his return and there was confirmation from his attorney he owned an apartment which he had inherited.
Marques-Santos also claimed he had a cousin who would support him and had significant savings in the bank.
The Brazilian met his victims - three in Nelson and two in Dunedin - through the gay dating app Grindr.
He would meet the men, watch them enter their Pins while they made an eftpos purchase then, while in their homes, would spike their drinks with Clonazepam.
While the victims were unconscious, he would take their bank card and go on a spending spree.
Marques-Santos swindled more than $10,000 in a matter of weeks.
The first time he appeared before the board, his stay behind bars was described as "uneven".
"He has made various allegations against fellow cellmates, prison staff, and the suggestion is he can be manipulative," the report said.
Marques-Santos' plight worsened when he was attacked by Wheble.
The man grabbed him from behind, and used his right hand to inflict an 8cm cut to the victim's throat, which narrowly missed the carotid artery.
After others intervened, Wheble twice stomped on Marques-Santos' head and followed it up with five football-style kicks as he lay in the recovery position.
Marques-Santos was airlifted to hospital, where he received 15 stitches to his neck as well as treatment for a nasal fracture and severe bruising.
He wrote to the Otago Daily Times saying he was "alive by a divine miracle" and praised other inmates who helped him.
"I remember some flashes of Wheble standing close, punching me," he wrote.
"I was saved by another prisoner who quickly blocked the bleeding by putting his top around my neck ... I was choking on my own blood."
The conditions of Marques-Santos' parole included a ban from New Zealand and from contacting his victims.
