In June 2024 Jake Danby hit two Aboriginal men with his car on a Darwin street, killing one and injuring the other.
When sentenced he was given a 12-month community corrections order, with five months in home detention.
Following public uproar the Northern Territory Director of Public Prosecutions appealed the sentence as "manifestly inadequate".
In Darwin on Friday three judges sitting as the Court of Criminal Appeal upheld the application and increased Danby's home detention period from five months to two years under an extended community corrections order.
Delivering their decision Chief Justice Michael Grant said Danby was also required to wear an electronic monitoring device.
It emerged in his earlier court case that the 24-year-old had bragged in text messages that the man he killed was an "oxygen thief" and he would not go to jail.
He called it a "two for one combo" and texted it was "pretty funny watching them roll around on the road after going over my bonnet".
The prosecution argued on appeal on December 11 that the text messages elevated Danby's crime to the aggravated level.
Prosecutor Pat Williams said a jail term of more than two years was required given the seriousness of the offending and public expectations.
Defence counsel Jon Tippett argued that the sentencing judge had taken note of Danby's text messages and while being appalled by them gave them appropriate weight.
Supreme Court Justice Sonia Brownhill had given his client a chance of rehabilitation and counselling and he was abiding by his corrections order amid public condemnation of his actions, the lawyer said.
"The renunciation in this case has been a tarring and feathering by the community," Mr Tippett said.
Courts shouldn't sentence people on the basis of their stupidity or vile comments, he said.
Danby was not in court on Friday and Mr Tippett declined to comment on the revised sentence outside court.
NT Attorney-General Marie-Clare Boothby has come under fire over the Danby case, accused of not reporting a conflict of interest after it emerged he was her sister's stepson.
Ms Boothby said she never attempted to hide the fact Danby was an extended family member and at no time was she or her office involved in the criminal matter.
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