CCTV footage released by investigators shows Downer resident Henry Khinzaw, 36, flying into a rage on an ACTION bus.

According to agreed facts tendered to the ACT Magistrates Court on Friday, Khinzaw had boarded the bus through the rear door in Dickson, without paying, on the morning of October 2 last year.

When the vehicle stopped at Westfield Belconnen just before 9am, Khinzaw was slow to head for the exit.

The rear door was already shutting by the time he reached it, and it closed on him three times as he tried to get off the bus.

An incensed Khinzaw began yelling at the driver, saying words to the effect of: "You did that deliberately."

He then walked to the front of the bus and threatened to "f---ing kill" the driver.

Khinzaw reached out and violently grabbed the driver's left cheek before hopping off the bus, briefly turning back to spit at the driver through the open front door.

Police were able to track him down after another bus driver, who had known Khinzaw for about 15 years, saw CCTV footage of the incident in the media and came forward to identify him.

The 36-year-old was charged with common assault, to which he pleaded guilty.

Khinzaw appeared in court for sentence on Friday, sitting in the public gallery with his phone consistently making noise as he waited for his case to be called.

When he eventually reached the bar table, having paused en route to loudly declare he was putting the device on airplane mode, he recounted some of what had happened on the bus.

"[The door] hit my face," he told Special Magistrate Jane Campbell.

Khinzaw's Legal Aid lawyer, Helen Hayunga, conceded her client's behaviour had been "intemperate" and "a little brazen".

But she sought to put it in context, saying the 36-year-old had believed the driver struck him with the door on purpose.

In sentencing, Ms Campbell said she was not satisfied that was the case.

She said even if it had been, it would not have been an excuse for Khinzaw to assault a man who "should be free to do his job without the interference of disgruntled passengers".

Ms Campbell told Khinzaw that at the age of 36, he was "getting on in years".

Khinzaw replied: "I still look young and feel young."

The magistrate accepted that this might be true, but warned Khinzaw he had to start acting his age.

"It's time to grow up," Ms Campbell told him.

She imposed a 12-month good behaviour order.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: