Ms O'Brien was on the league's Tainui Regional Executive Board for 12 years and served as president of the Matua Branch.
The 74-year-old said she enjoyed seeing positive outcomes for Maori families.
"Especially those who have alcohol and drug abuse issues, lack of parenting skills because it's never been role modelled to them ...
"I am a mother, a grandmother and a great grandmother so those support tools I use, I use them with my own family, too," she said.
Before being involved with the league, Mrs O'Brien was an educationalist, who taught at Auckland Girl's Grammar School, Otumoetai College and Tauranga Girl's College.