The 26-year-old was fined £30,000 by the England and Wales Cricket Board after the incident in Wellington the night before a one-day international.
England lost the match the next day with Brook scoring just six.
"I've learnt from my mistakes," Brook told reporters in Colombo, where England face Sri Lanka in a three-match ODI series beginning on Thursday.
"I've reflected a lot and I know it wasn't the right thing to do," he said, speaking publicly for the first time about the incident on the tour that preceded the Ashes series, which England lost 4-1.
"I want to apologise to my team-mates, the fans and the ECB for putting them in a tricky situation," said Brook, who will lead England in next month's T20 World Cup in India and Sri Lanka.
"It will never happen again. I'm extremely sorry."
Controversy dogged England's Ashes series, with allegations of poor preparations, muddled team selection and a "drinking culture" in the England camp.
England players were photographed spending hours in bars during a mid-series beach resort break, with a video of an apparently drunk Ben Duckett circulating on social media.
The three-match ODI series in Sri Lanka will be followed by three Twenty20 internationals, England's final warm-ups before the T20 World Cup begins on February 7th.
Brook said the series would be a timely litmus test for his side, who have been searching for rhythm and results.
"It's important to get used to the conditions, the climate and the heat," Brook said. "We are looking forward to a competitive series."
England's white-ball fortunes have nosedived since their forgettable 50-over World Cup campaign in India in 2023 where, as defending champions, they failed to make the semi-finals.
Since then, they have lost six of their last seven bilateral series and endured a Champions Trophy to forget, bowing out after losing all three group games.
"We would like to be a little more consistent, absorb pressure and stay in the game for longer periods," Brook said.
"Yes, we've lost a few series, but I feel we're heading in the right direction."
Sri Lanka are wrestling with selection issues ahead of co-hosting the World Cup.
Charith Asalanka was removed as T20 captain late last year but continues to lead the 50-over side.
Injury-prone strike bowler Dushmantha Chameera has been rested for this series, while there remains uncertainty over the availability of leg-spinner Wanindu Hasaranga.
"I would have liked to have both in the team," Asalanka said.
"But we have to look at the bigger picture, which is the World Cup. We haven't made a final call on Hasaranga yet."