The paid role will be for about 15 to 20 days a year.
Head of tourism for Ateed (Auckland Tourism, Events and Economic Development) Jason Hill said it was fantastic to have secured such a well-respected and internationally recognised ambassador for Auckland.
"JK's rugby pedigree, both in his time playing as an All Black and then his international coaching career, means he will resonate well with the visiting rugby fan,'' Hill said.
"This, coupled with the inspirational work he's done to raise awareness for depression in recent years, means he remains very popular with the New Zealand public and we feel fortunate to now be working with him to promote Auckland."
Kirwan was head coach of the Blues franchise for three years, resigning in 2015, and said there were some issues attracting players because of the perceived difficulty of living in the city.
There was a stigma about Auckland's traffic but his team had a farmer, Tony Woodcock, and many in other parts of the country were aware of how easy it was to get into rural areas quickly.
He said a highly successful Blues team would be good for galvanising the city but it wasn't crucial for celebrating sport.
''I'm all for closing Sandringham and having a street party regardless of the game.''
He is also in favour of calling time at Eden Park and building a multi-use stadium on Auckland's waterfront.
While Eden Park was home during his rugby career, sentiment shouldn't play a role in any decision about a move.
''I love the place, it was my home but we've got to keep moving.''
In a video released today, Kirwan highlights the vast array of tourism experiences Auckland offers, targeting the Lions fans travelling to Auckland for the tour which kicks off in Auckland with a game against the Blues at Eden Park on June 7. Two test matches will be held there, too.
Kirwan ambassadorial posting was announced at the Trenz tourism marketing event being held at The Cloud in Auckland. Next year's Trenz will be held in Dunedin.