The 72-year-old leaves with the HKRU in a sound financial position and his legacy also led to the development of women's rugby in Horowhenua-Kāpiti, the Union's investment in the Hurricanes, and the formation of a new system of governance.
The union appointed a six-person Board of Directors to the HKRU, with legal, managerial and accounting expertise, with the majority support of club delegates.
"The board has worked extremely well and has added another dimension and is important to sound governance," he said.
HKRU has a record high number of registered players with 4304, and has produced 12 consecutive financial surpluses, a feat which is believed to be unrivalled by
other provincial unions.
"It's a small surplus this year. But it's a surplus," he said.
John Mowbray, who was estimated to have attended more than 600 meetings during his time, said he was enthusiastic about the future of the HKRU and rugby in the province.
"I'm confident our Union is in good shape to face the challenges ahead and look
forward to still being a part of the rugby community in Horowhenua Kāpiti," he said.
"It's been a priviledge and I've enjoyed every minute of it."
Mowbray pointed out that the two current All Black hookers Dane Coles and Cody Taylor were products of the union, and that small unions remain an integral part of New Zealand rugby.
Meanwhile, he commended the HKRU Chief Executive Corey Kennett and staff at the HKRU who he said worked hard and were contributing to the growth of the game in the province.
Kennett thanked to Mowbray for his service.
"I'd personally like to thank John for his dedication, hard work and vision for our Union in being Chairman for the past 15 years," he said.
"John has overseen the Horowhenua Kāpiti Rugby Football Union become one of the leading Heartland Unions and we will be forever thankful to him for that."
