Wilkie was among the parents called to take their children home.
He arrived with his wife Ann, a Counties Manukau detective.
Once his daughter was in the car, he crossed to one of the boys sitting on the grass verge and kicked him firmly in the shin with a bare foot. He kicked the next youth in the thigh and demanded his full name, then said: "That's the last time I ever see your f***** face."
He thanked the police officers present, then drove off.
Lawyer Richard Earwaker released a statement on Wilkie's behalf saying his actions were those of a concerned father upon discovering his daughter had taken alcohol and sneaked out at night to meet other young people.
"He had been contacted by the police in the early hours of the morning and, as a result, went to pick his daughter up from the roadside. He was upset and concerned for her safety.
"He acknowledges his subsequent actions were inappropriate and showed poor judgment. He is extremely remorseful and has always accepted responsibility for his actions, which is reflected in his early guilty pleas." Earwaker said it was hoped the acceptance of the charges would minimise any further stress to the boys and their families.
In May, when interviewed by the police, Wilkie described the kicks as having no more force than that used in a friendly "pat on the back" when greeting someone.
However, the summary of facts said both officers were disturbed by what they saw, knowing the defendant to be a senior policeman, and reported the incident to their supervisor at the conclusion of their shift.
The father of one victim said he didn't believe Wilkie was fit to continue as a policeman. Given his high rank and extensive training, he should have known better.
"He wasn't acting in self-defence ... there was no physical provocation or weapons."
His son had been at the park only minutes when the police arrived and was sitting calmly with the group when Wilkie showed up. "The only violent one was Richard."
Macleans College principal Byron Bentley said Wilkie resigned by email several weeks ago "for the school's sake. But I said to him, frankly, I don't think that was necessary and I hope that he can come back on the board as quickly as possible.
"He is a great guy, a good man ... very caring, very interested in the school, very involved.
"There's major sympathy in the community and from the board and senior staff."
There appear to be no legal barriers to Wilkie's return to the Macleans post. But School Trustees' Association president Lorraine Kerr said the board would have to think hard about allowing him back.
"I think given the role of the board is important ... in that we are the guardians of everything that goes on in our schools, including keeping everyone emotionally and physically safe, you would hope that common sense would prevail."
The parent of the victim, however, was adamant he should not return.
"He may have a legal right to serve on the board, but he hasn't demonstrated appropriate behaviour, and it sends the wrong message."
A Counties Manukau police spokeswoman would not say if Wilkie had been stood down.
Wilkie has been with the police since 1981 and has not previously appeared in court as a defendant.
So far, no conviction has been entered, at Earwaker's request.
A restorative justice conference has also been requested.
