But the NSW Law Enforcement Conduct Commission stopped short of finding other officers tried to cover up the May 2023 incident when they didn't declare the incident publicly.
The 46-year-old inspector crashed a work-issued vehicle in a northern Sydney tunnel and left it damaged on a street after a spending several hours drinking with other officers in the city.
However, he wasn't charged with high-range drink driving until six months later.
A police watchdog has found a senior officer guilty of serious misconduct for leaving a crash scene. (Joel Carrett/AAP PHOTOS)
The commission found the officer, whose identity has been suppressed by a court, guilty of serious misconduct for leaving the scene of the crash to avoid a blood-alcohol reading.
It also declared he had been "deliberately dishonest" in his answers on an insurance claim form for the car he crashed.
Internal police documents previously released to state parliament revealed the high-ranking officer lodged an insurance claim saying the crash happened when he "fell asleep" at the wheel.
He was subsequently accused of driving with a blood alcohol level of more than 0.15, an allegation he denies.
The officer was also treated more leniently by his commander and in a police review of his driving, which the watchdog said led to other officers losing confidence in the integrity of the force.
Chief Commissioner Peter Johnson acknowledged the general public had the right to know that police officers were dealt with the same way as other citizens when alleged criminal incidents occur.
"But there is a second important audience ... other NSW police force officers watch to see if senior officers are dealt with in the same way as junior officers," he said.
"If there is not equitable treatment of all police, it can lead to dissatisfaction in the ranks of the police generally."
Police Commissioner Karen Webb previously denied the officer was "protected" in the investigation. (Dan Himbrechts/AAP PHOTOS)
Police did not issue a public statement about the allegations until media reported details of the incident, prompting suggestions its leadership wanted to cover up the events.
But the commission found no evidence the lack of public disclosure involved impropriety, while noting it had hurt the reputation of the force.
It emphasised "the equitable and transparent treatment of all police" in the handling of allegations against officers.
NSW Police Commissioner Karen Webb previously denied any cover-up, saying disclosure had "slipped through the cracks" rather than being avoided deliberately.
Ms Webb denied the officer was "protected" during the six-month delay in charges being laid, saying it was not unusual for there to be a drawn-out investigation.
The officer is due back in court on September 27.
High-range drink-driving carries a maximum jail term of 18 months.
