He said he first noticed the baby crying "in a distressed way" through his headphones as he sat watching a movie.
"It was sort of a cry for alarm, trying to get attention, come and help me someone and I thought why is the baby crying like that? And I could see they were looking off into the distance with a smirk on their face and I thought that's not right. so I just stood up and had a look over the father's shoulder ... and the child saw me and stopped crying."
He said the father then looked up at him and said "what are you looking at, go back to your seat".
"The child was lying on its back in the middle seat with his head over the mother's leg and so the neck was over her arm rest and she was holding the forearm down on the child's throat and there's tears coming down its face and it was crying and waving its arms around.
"[Father] had his hands holding the child's ankle to the seats, so the child couldn't move and it was being forcibly held there."
In his reserved decision from the March hearing, Judge Stephen Harrop said Gallon likened the parents' actions to "child abuse or child torture".
Judge Harrop wrote after Gallon challenged the father about what he was doing, the father called the inflight service manager.
"She did not consider there was anything wrong with the parents' actions and asked Mr Gallon to return to his seat, which he did," the judge wrote.
However, Gallon, an IT consultant and evangelist, persisted in talking to the family and he was eventually moved four rows forward, which he agreed to do.
Gallon believed by not doing anything about the parents' actions the inflight service manager was condoning the parents' behaviour.
He then complained by writing a note to the captain expressing his concern about any possible mistreatment.
He wrote, "Sir, I am concerned for the well-being of the child in row 6, who has been
restrained against its will, to the point of tears ... I can hear some resemblance of screams over the noise of the aircraft.
"If you will not assign supervision to the child, then you are choosing to tolerate child abuse. Please, do not treat lightly, the abuse of children in your aircraft."
He was given a final warning and threatened with being met by police and for a short time became compliant before again returning to where he was originally sitting.
After landing, Gallon was met by police who issued him an infringement notice, which he disputed and the disorderly behaviour charge was subsequently laid.
In giving her evidence to Judge Harrop in the March hearing, the staff member said she was about five to six months' pregnant at the time and that she and the other crew were all very tired after a few days of international flying.
But Gallon said his conduct was driven "entirely by a genuine concern for the welfare of the child and that in no respect did he behave in a disorderly manner towards [the victim], or any other crew member".
He was eventually convicted and fined $750 by Judge Harrop.
However, Gallon appealed and in the High Court at Wellington Justice Francis Cooke quashed his convictions stating "the facts did not support a conviction of disorderly behaviour", Stuff reported.
He said Gallon was treated in a fair but firm way in accordance with Air New Zealand policy.
"That is what happened. After being dealt with in a firm way Mr Gallon complied. The system for maintaining order worked as it was supposed to," Stuff reported.
No retrial was ordered.
Gallon told the Herald the high court's decision was a relief.
"That's a load off my mind and that's me as a person, that to me was good news to receive."
However, he was disappointed as he felt his actions could be misconstrued by the public.
"When I walk around town, and most people are parents with babies that cry and they're going to think it's unreasonable for me to get upset that they're basically just feeding their child and resting their hand against its chest.
"There's something wrong with that, in the way people read that and then look at me as being someone who objects to that, that's not quite how it happened, you know. It's pretty serious when you're crushing a child's throat.
"And for the flight attendant to say no, go back to your seat, that's not okay in our world."