But his fall from grace was completed on Wednesday, after the ACT Supreme Court sentenced him to five years behind bars for child sexual abuse that saw a 12-year-old fall pregnant.

Nona, 42, shot to fame as an artist in his 30s, his work given pride of place in galleries across the world, including the National Gallery of Australia and Parliament House in Canberra.

But the Australian Federal Police have sat on an arrest warrant issued for Nona in 1997-98 for allegations of the sexual abuse of two girls during his time studying visual art in Canberra.

The warrant was not executed for more than a decade, a delay described by his barrister John Purnell, SC, as "inexcusable" on Wednesday.

Mr Purnell said police would have clearly had no issue tracking down Nona. His client, he said, had been selling artwork to members of the Australian Federal Police and was constantly in the public eye.

Nona was eventually charged and put on separate trials for abuse against each of the girls. He was found guilty in the first, and sentenced to seven years and six months by Justice John Burns early last year.

He was found guilty in the second trial, which was a retrial, late last year. Chief Justice Helen Murrell on Wednesday sentenced Nona to five years imprisonment for crimes mainly against the younger victim, aged 12 or 13.

Parts of the two sentences overlapped, creating a total sentence of nine years, with a non-parole period of four years and six months.

He has been in custody since 2012, and will be eligible for release in February 2017.

The court heard extensive evidence about Nona's history, growing up on the remote Badu Island in the Torres Strait. He was brought up in detached and abusive circumstances, the court heard, and left at the age of 14, travelling to Thursday Island, Cairns, and then coming to Canberra to study in his early 20s.

The move left him alienated from his family and culture, the court heard, and he turned to alcohol, often drinking until he blacked out.

Chief Justice Murrell said his upbringing also blurred the "bright line" between appropriate and inappropriate behaviour toward children.

"None of this excuses the offender's conduct, but it does provide context," she said.

His actions, the judge said, would have had a profound and lifelong impact upon the victim.

Earlier in the day, Nona gave evidence of the hardship he faced in prison, where he has been assaulted three times.

He said he shared a special connection with the land, and was a traditional hunter, who spent long stretches on the ocean.

"When you compare that [to] now, when I get locked in, it's very hard," he said.

Nona said he often thought about other Indigenous inmates who had taken their lives, and often thought like them.

"Because we are not belonging to inside, confined space ... we are nature people.

"We don't get locked in."

Chief Justice Murrell acknowledged his strong connection to the land, and that he faced particular difficulty while incarcerated.

She also said he had made a significant contribution to Torres Strait and Australian culture through his work and had not reoffended in the 17 years since the offences.

Nona's works have been pulled from many galleries and from Parliament House.

He said that, once released, he hopes to return to Badu Island and work on a boat.

"I want to get on one of the boats and stay out in the ocean like I did when I was young," he said.

Nona has appealed against his first sentence of seven years and six months, imposed by Justice John Burns, but faces a simultaneous appeal by the Director of Public Prosecutions.

A decision on both appeals is yet to be handed down.