He was sentenced to two years and eight months in prison - a sentence he has now served.
However, Hwang took his case to the Court of Appeal, asking for a retrospective discharge of the conviction.
In an affidavit presented to the court he said he had found it “difficult, bordering on the impossible” to secure meaningful employment because of the conviction.
He has also found that having an arson offence on his record has caused him difficulties for obtaining accommodation.
“The gist of Mr Hwang’s submissions on this point was that prospective landlords refuse his application to tenant their property as soon as they learn of his conviction,” the Appeal Court justices said in a recently-released decision.
The Court of Appeal dismissed the application, meaning that Hwang’s conviction still stands.
Hwang was connected to the Taupō Sushi business through a woman who worked there.
The shop had been in business for about a year, and got behind on its rent. Then the operator was taken into custody on immigration matters.
The company was facing trouble on multiple fronts: from the Taupō District Council on health matters due to rotting food, from the landlord for back rent, and from the construction firm which had fitted the shop out and not been paid.
The construction firm took legal action, then chained up the shop front and boarded up the rear door.
In the early hours of November 30, 2018, Hwang and the woman drove to two service stations and bought methylated spirits from one.
At the shop, Hwang broke a rear window, poured methylated spirits on a bench inside and lit a fire.
The resulting blaze completely destroyed the sushi shop, a store next door, and affected other businesses.
Total losses ran to $2.7m.
The first firefighters who entered the burning building were forced to retreat as the heat was so intense and they faced the risk of roof collapse and toxic gases.
In addition to the difficulties getting employment and accommodation, Hwang told the court that the conviction also adversely affected his ability to travel, including to Korea where he was born and has family.
Hwang, who has been diagnosed with an autism spectrum disorder, also said the conviction had an “ongoing impact” on his mental health.
Crown lawyers, however, told the Appeal Court that Hwang had accrued several convictions for dishonesty since his arson offence.
“It is fair to say that Mr Hwang’s dishonesty offending is significantly less serious than the arson and, although Mr Hwang did not say as much, might reflect the difficulties that he has experienced in obtaining employment,” the Appeal Court decision said.
In dismissing the appeal, the justices said the consequences of Hwang’s arson conviction were not out of proportion to the gravity of the offence.
“We can only repeat that this offending was extremely serious and the consequences of conviction that Mr Hwang has advanced ... do not come close to the level required to put a discharge without conviction in reach.”
The decision said that Hwang was making “impressive” efforts to put his offending behind him and set himself up for the future.
“We congratulate him,” the Appeal Court judges said.
“At age 30 it is still relatively early days for Mr Hwang.
“The more distant in time his conviction becomes, the more it is likely to be treated as an isolated, albeit serious, event.”
Ric Stevens spent many years working for the former New Zealand Press Association news agency, including as a political reporter at Parliament, before holding senior positions at various daily newspapers. He joined NZME’s Open Justice team in 2022 and is based in Hawke’s Bay. His writing in the crime and justice sphere is informed by four years of frontline experience as a probation officer.