The chase reached speeds up to 60km/h and forced some bystanders to leap off the side of a footbridge to avoid being hit.
Gibson was charged with dangerous driving after the incident and was discharged without conviction.
He was able to escape conviction again today, with Judge Chris Tuohy acknowledging the life events that led to Gibson's offending.
According to defence lawyer Letizea Ord, Gibson's life was "spiralling out of control" at the time.
"His personal life had been unravelling," she said at an earlier hearing.
It began with an incident of personal tragedy, and was exacerbated by an "extremely heavy police workload", a friend being shot at, and the loss of two grandparents in the space of nine days, she said.
"He slowly became more and more disillusioned ... [and] realised that his life revolved completely around the police."
Ord said Gibson fell in with the wrong crowd.
"He describes his life spiralling completely out of control and using a huge amount of alcohol to essentially self-medicate, and because of his associations outside of the police he began using recreational drugs.
"This offending, whilst on the face of it could be said to be serious, was essentially the defendant, while extremely intoxicated in the toilet, giving a man a substance for that person's personal use."
She said there was no money exchanged, and the quantity involved was "very small".
The night of the offending was the same night his wife left him.
Gibson has since undertaken counselling sessions, an alcohol and drug assessment, has stopped using recreational drugs, and has reduced his alcohol intake.
"Essentially we have someone who has had and devoted a number of years to policing and has worked hard in that role, received significant promotions, and been an active and productive member of the police force."
Crown prosecutor Jamie O'Sullivan said at the earlier hearing Gibson was still a paid member of the police, but was suspended.
She said Gibson's argument he had no memory of the offending did not show he was taking responsibility.
"He knows that this is illegal, he knows the impact the dissemination of drugs within the community can have," she said.
"He knows purchasing, supplying drugs, means that you're supporting the drug trade. He was supporting illegal criminal activity and indeed to that end, probably funding it."
O'Sullivan said Gibson made a choice to associate with people who treated this behaviour as acceptable.
"There's no question that he should have known, and did know better."
Ord initially intended to apply for permanent name suppression, but Judge Tuohy said there would be a "significant loss of confidence in the justice system" if the public became aware the court had allowed a police officer to be discharged without conviction and to keep his name secret as well.
According to the summary of facts, Gibson met the other person in the bar toilet in August last year and began talking with him about sports.
He was spotted by an off-duty police officer offering a line of MDMA to the other man, in exchange for the other man adding him as a friend on Facebook.
The other man defriended and blocked him the following day.
In court today, Judge Tuohy described Gibson's offending as a "loss of moral balance".
He said part of his disillusionment with the police related to Gibson not feeling supported by his employer after the dangerous driving incident, and another operation he was involved in.
"Weighing up the gravity, the offence itself is intrinsically a serious type of offence, but this one is right at the bottom of the scale for offending of this type."
Judge Tuohy pointed out Gibson had lost his successful career as a result of this offending, and a conviction would affect his ability to gain another job and continue his role as a marriage celebrant.
He discharged Gibson without conviction and ordered him to make a reparation payment of $2500 to an appropriate drug rehabilitation charity.
A police spokeswoman told the Herald police have accepted Gibson's resignation.
"The public rightly expects high standards from police staff. We set high professional standards for ourselves and demand integrity from our staff, in terms of judgment, choices and actions," the spokeswoman said.
"The vast majority of our staff act in accordance with police's values. When an officer's conduct is not in line with police's values we will not hesitate to investigate and deal with the matter appropriately."