He was eager to pick up his son and buy the boy some McDonald's as a treat at the end of the week.

But, as it had throughout the proud cop's 13 years with ACT Policing, duty called near the end of his shift.

It was a "stinking hot" Friday afternoon in January last year when word came over the police radio that three men were fighting in a Gungahlin street.

And so Detective Sergeant Taylor went to The Valley Avenue, where he told a court on Friday his life had changed forever.

Court documents reveal police arrived at the scene to find two men including an intoxicated Robert James Reid, who was bleeding from a gash on his head and sporting what appeared to be two broken teeth.

The 38-year-old told officers he had tripped over and smashed his face on the footpath, and initially there was no sign of danger.

That changed when Reid's son drove up and told police he had hit his father earlier on.

Officers informed the teenager he would be taken into custody, prompting him to angrily approach his dad.

"C---, I'm getting arrested because of you," the 19-year-old ranted.

"Wait until I get out, c---. I'm going to f--- you up."

Fearing the teenager was about to assault his father, Detective Sergeant Taylor restrained him and led him towards a police car.

While his back was turned, Reid charged towards the officer and grabbed him around the throat.

Detective Sergeant Taylor struggled to breathe as Reid pulled him to the ground in a headlock, holding on for nearly 10 seconds.

Other officers were forced to Taser Reid, with four of them required to haul the Palmerston man off their colleague.

Detective Sergeant Taylor trembled in the ACT Magistrates Court on Friday as he spoke of the incident.

He revealed he had contemplated reaching for his gun and shooting Reid as he struggled to release the "indescribable pressure" on his neck.

"I couldn't breathe," he said. "It was bloody terrifying."

He praised his colleagues, saying that without them, he would be dead because Reid was not letting go.

Detective Sergeant Taylor also told the court he suffered from post-traumatic stress disorder and anxiety because of the attack, which had left him unable to return to operational duties.

He called Reid "a coward", and challenged Magistrate Peter Morrison to impose a sentence that would prove the courts "give a shit" about police officers.

Reid, who pleaded guilty to one count of choking, suffocating or strangling a person, sought to explain himself when he took to the witness stand.

He said he had been "scared shitless" when the police approached him, having previously had several negative interactions.

He claimed that on one occasion, when he was a homeless teenager, officers "beat the living shit" out of him.

Reid's lawyer, Gabrielle Knight, told the court her client's "unique experience as an Aboriginal man" with police went some way to explaining his behaviour.

She said he had "overstepped the mark" while trying to protect his son from what he had perceived to be "heavy-handedness" by the police.

Ms Knight urged Mr Morrison not to impose a sentence of full-time imprisonment, saying one would not be the best option for Reid's rehabilitation.

Prosecutor Julia Epstein said a jail sentence was clearly warranted, but whether Reid should serve it behind bars or in the community was a matter for the court.

She stressed that Reid had a "significant" criminal history, and that he had caused lasting psychological damage to a victim who was attacked from behind when he was vulnerable.

"The community rightly finds this type of offence abhorrent," Ms Epstein said.

Mr Morrison sentenced Reid to 20 months in jail, but ordered the term be served in the community by way of an intensive correction order.

He told Reid his response to the incident had been "unreasonable", but took into account his "deprived" upbringing and its ongoing effects.

Urging Reid to comply with the conditions of his sentence or risk being locked up, Mr Morrison admitted the sentence involved "a fair degree of leniency".