Rev Te Wainohu was later wounded in the back but went on to accompany the contingent in France.
In 1920, at the age of 38, he died from stomach cancer in Wairoa, where a statue remains of him in uniform, unveiled by his friend Sir Peter Buck.
More than 1000 people, including Apirana Ngata and Sir James Carroll, attended the unveiling.
Rev Te Wainohu married but died childless.
His sister's granddaughter, Neti Whatuira, was one of 20 whanau attending a Wellington dawn powhiri for the exhibition, which features seven other New Zealanders' stories.
She said she never met her great uncle or her grandmother, who died on the same day as her husband in the world flu epidemic.
"They left four of them orphaned, aged 3, 4, 5 and 6, that were brought up by her father," she said.
She expected the powhiri to be a spiritual experience and looked forward to learning more about her father's uncle.
"A lot of them didn't tell their stories. Looking at it online makes you real teary."
Te Aute College old boy's recorded pre-battle prayer, waiata and haka will be at the exhibition.
"All those involved met up at the location on a hill top at Mount Crawford in Wellington," Te Papa researcher Amber Aranui said.
"It was still daylight, the sun was shining and the wind had mysteriously died down.
"It was to be a still, calm, eerie night."
The haka was recorded at dusk, when "the atmosphere had changed".
"Our voice actor, Rev Michael Tamihere, had a special connection to Chaplain Te Wainohu. Not only was he from the same area, but he was also a man of God and a similar age to Te Wainohu when he was on Gallipoli.
"We all gathered around him for his delivery of the sermon. It was cold and dark, yet we were captivated as he began to speak. It was the most amazing and moving experience.
"Many of us present were affected, there were even tears shed as we were all caught up in the moment.
"I could almost picture myself there at Gallipoli on August 6, 1915, prepared for battle, being given those words to hold close."
The exhibition will run for four years.
It took 24,000 hours of labour and $8 million. Realistic-looking larger-than-life sculptures, including details such as tattoos and varicose veins, are surrounded by screens with images from their personal diaries.
Neti's husband Trevor said the Wairoa statue was in a reserve that had "gone backwards".
"We used to play on him as kids - we lived just down the road from there by the Ferry Hotel," he said.
"They wanted to move it back to Mohaka, but I guess finances are stopping them."
"He looks lonely," Neti said.
