The revelation was greeted by loud cheers from the crowd of around 500 and a deep breath from Dynes.
Speaking to the Herald following the speech, Dynes said he was “really, really nervous” leading up to it but “quite calm” on the day.
“Definitely (felt) like a weight off my shoulders, it was a nice feeling just to let it all out and just be me, I guess,” he said.
Dynes told the Herald he wrote the speech back in September but it “took a while to sink in”.
He now hopes it’ll encourage other young people to feel comfortable in doing the same.
“If I can help at least one person, then that’s a good thing, isn’t it?” he said.
Dynes’ speech is believed to have been the school’s first to ever receive a standing ovation.
His mother Katrina Dynes said she was incredibly proud of her “bold and courageous” boy.
The speech and its reception showed how “brave, loved and strong Harry is”.
The young man from the small town of Waikoikoi plans to spend his summer painting and working at the local Four-Square before he heads off to the University of Otago to study for a Bachelor of Communications.