Mealamu, who has played 126 tests, was always expected to hang up his boots after the global tournament - he said farewell to the Blues after this season.
In an announcement in Wellington this morning, Mealamu added he was looking forward to a new challenge. His ambassador role will see him working for New Zealand rugby for the next two years.
Mealamu said he was "excited and humbled"by the opportunity.
"I've loved my time as a rugby player here in New Zealand and loved being part of all the teams I have represented, particularly the All Blacks. While there's a little bit more I want to achieve this year before I hang up my boots, it's cool to know that I am going to be still involved in rugby in this new role.
"I'm grateful for the opportunity to support the game which I love and which has given me so much, and in my Rugby Ambassador role I look forward to giving back to the game, to the Auckland region, the wider community, and to New Zealand Rugby."
Mealamu will also be involved in promotion of New Zealand Rugby's other community, educational and social responsibility initiatives (e.g. the Applaud sideline behaviour programme) and will also play an ambassadorial role within New Zealand Rugby's commercial, charity and VIP programmes.
New Zealand Rugby Chief Executive Steve Tew said: "We're delighted to announce Keven's appointment as a New Zealand Rugby Ambassador.
"He's hugely respected by not only our organisation, but the wider rugby community. He has huge mana amongst the Auckland communities as well for everything he's achieved and is the perfect person to carry out this role.
"As an Aucklander, Keven is well aware of the challenges we face in the greater Auckland region. He's ideally placed to help us encourage more players, coaches and referees to embrace the game in the region," Tew said.
