A jury found Arthur Marshall Hoyle, 67, guilty earlier this year of raping the student, making advances on two others, and showing another a pornographic PowerPoint slide.

The offences happened in Hoyle's office in April 2015, after he had invited the students in to discuss allegations of cheating in their essays. The victims were all female and from overseas.

He was found guilty of a total of eight offences, including two of rape, and he was acquitted of a further two acts of indecency.

Hoyle, who had taught at the university for 21 years, appeared in the ACT Supreme Court on Friday for the second day of a sentence hearing before Justice Michael Elkaim. On the first day, the court heard from the former lecturer's victims.

On Friday, the court heard from defence witnesses, including the man's daughter and brother, who spoke of Hoyle's good reputation among students and his colleagues.

They also expressed their shock at the offences.

"If I looked at the 22 years that I've known him, this in my view would be a complete aberration," a close colleague and Hoyle's former head of school at the university said.

The court also heard from a doctor who said Hoyle had dementia, brain disease and brain damage that likely went back years and would continue to worsen. The geriatrician said the symptoms of the man's brain disease included disinhibition and a loss of impulse control in social situations.

After hearing from the witnesses, the prosecutor and the man's defence barrister, Justice Elkaim sentenced Hoyle to four years jail with a non-parole period of two years and six months.

Justice Elkaim did not accept that Hoyle's behaviour in April 2015 was "in any way a product of any brain damage or disease," saying that such a conclusion would be "entirely inconsistent" with references about his general functioning at the time.

He said the brain damage did not reduce Hoyle's moral culpability for the offences. The judge also noted it was never part of any defence at the man's trial that his actions were the product of cognitive impairment. "To the contrary, his defence was that the events did not happen at all," he said.

He said the jury rejected defence suggestions the women had made up their allegations to overcome any findings of cheating, which may have stopped them finishing the course.

"The jury was of the view that the offender had taken advantage of the students' vulnerability ... seeking to obtain sexual gratification from them," Justice Elkaim said.

He noted the victims were overseas students who had paid a lot of money to go to university in Australia, were on visas, and facing allegations of cheating.

And an aggravating feature of the man's offending was that he was a lecturer at university and teaching students much younger than himself, the judge said.

He was in a position of "authority, trust and influence".

"He abused this position," Justice Elkaim said.

But the judge accepted evidence from the man's daughter that Hoyle was a loving and caring father and husband, and noted he committed the offences at the end of a notable career.

"I accept that the convictions will overshadow all of the offender's achievements," Justice Elkaim said in sentencing, "and remain a stain on his character for the rest of his life".

Hoyle will be eligible for parole in October 2019.