In a message addressed to Prime Minister Jacinda Ardern on Instagram today, King revealed he would be handing back the accolade - for services to mental health and suicide prevention - given the state of mental health services.
"Every day I ask myself, 'how can you wear this title when things haven't changed and so many are still suffering?'," King said in the statement.
"The truth is I can't. I know none of this is your fault Prime Minister and I know you truly care about our children but the system is broken and it seems no one is trying to fix it."
He referenced the scores of families who had contacted him, saying their children didn't qualify for counselling because they were "not suicidal enough".
King spoke of his optimism when Ardern announced $1.9 billion of mental health funding three years ago, but meaningful change was absent in his eyes.
"There was such a euphoric feeling in the air, full of optimism and hope and I believed with all my heart things were about to change, finally we had a Government who cared.
"Three years on I feel like we have let everybody down."
King's statement comes a day before the third edition of Gumboot Friday - an initiative raising money to provide free counselling for young people.
King would be walking 100,000m (100km) in gumboots around the Auckland Domain in an effort to raise $100,000 towards the $5 million goal.
In an opinion piece for the NZ Herald earlier this month, King launched scathing criticism at the Ministry of Health for not funding Gumboot Friday - a programme King claimed was more cost-effective and of a higher quality than the ministry equivalent.
"I am simply staggered that a resource that New Zealanders deem worthy of funding is being ignored by the Ministry of Health," King said in the article.
"It's not only reprehensible behaviour from the officials but continues the status quo where New Zealanders facing mental health challenges are left questioning if they're important enough to get help."
