Mark Kenneth Jenkin sat quietly in the dock of the NSW Supreme Court in Sydney but was seen repeatedly shaking his head as Justice Peter Hamill delivered his judgement on Thursday morning, almost a year after finding the 47-year-old not guilty of murder but guilty of the manslaughter of Mark Dower in 2015.

The court heard Jenkin, described by the judge as having a "short fuse and a vile temper", had a history of standing over vulnerable people for money and had previously targeted other residents in the Crana Place unit block where he lived.

Mr Dower, an alcoholic who spent years living and teaching in Finland before returning to Australia, was the recipient of pensions from both countries and was targeted by Jenkin as a result.

The court heard Mr Dower was taken from the unit of an acquaintance to Jenkins' unit on March 22 to "sober up" so Jenkin could have him attend court and give evidence about the origins of some money that police had previously confiscated from Jenkin. (Police suspected the money came from selling drugs - Jenkin said Mr Dower had given it to him.)

However, Jenkin instead subjected Mr Dower to a series of degrading and savage assaults, resulting in his death sometime between March 22 and March 28.

"I'm satisfied Mr Dower's death was the culmination of days of intermittent violence at the hands of Jenkin," Justice Hamill said.

"The nature of extent of his injuries paint a violent and traumatic picture of Mr Dower's last days....he suffered greatly."

After Mr Dower's death, Jenkin had a woman help him move the body, now sealed inside a surfboard bag, to a shared laundry at the unit block.

The bag and its contents were not discovered until April 16.

Jenkin was charged with murder on November 24, 2015. He was already behind bars at the time, serving a sentence for an unrelated break and enter.

While in custody, Jenkin conspired with his step-brother to murder the woman who had helped him move Mr Dower's body and whom he rightly feared would turn Crown witness.

He asked his step-brother to discover the woman's whereabouts and give her a "hot shot" - a deliberately lethal overdose of heroin - knowing she was a drug user.

The step-brother took steps to carry out the "amateurish" plan however Justice Hamill accepted it didn't amount to much as the co-conspirator was "somewhat incompetent".

Jenkin faced trial last year and was acquitted of murdering Mr Dower but found guilty of the lesser charge of manslaughter.

He was also found guilty of conspiring to murder the woman.

In court on Thursday, Justice Hamill noted Jenkin had a background of childhood trauma and disfunction, had been diagnosed with ADHD and anti-social personality disorder and, having spent most of his adult life behind bars for committing violent crimes, was largely institutionalised.

However, he was particular to point out Jenkins' own self-serving evidence he'd given in the witness box during the trial - which Justice Hamill largely rejected - and his apparent total indifference to Mr Dower's suffering.

"Like the rest of his behaviour, his conduct [in court] demonstrated a remarkable lack of empathy or remorse," Justice Hamill said.

He sentenced Jenkin to 19 years' jail, with a non-parole period of 14 years.

With time already served, Jenkin will be eligible to apply for parole in January 2030.

Justice Hamill expressed his sympathy to Mr Dower's daughter, who lives in Finland and did not attend the trial but prepared a victim impact statement to be read in court for sentencing.

"I wish to extend the court's deepest sympathy to Mr Dower's daughter and I commend her for her courage in providing a statement," he said.

"No sentence imposed on your father's killer will ease you pain."

He also thanked Mr Dower's friends for maintaining a "quiet vigil" over the proceedings.

"All human life is sacred. Almost every homicide has devastating impact on those affected by it," he said.