Gatland's All Black hopes hang on Lions' win
Gatland, a proud Kiwi, has a complicated relationship with New Zealand rugby that has become increasing fractious as the Lions tour has progressed.
As a player, he pulled on the famous All Black jersey 17 times and also scored a try against the 1993 Lions when representing Waikato.
As a coach, he hasn't hesitated to call out the world champions about tactics he sees as dangerous or borderline illegal.
It's raised hackles among Gatland's compatriots, including incumbent All Blacks coach Steve Hansen, who labelled his rival "desperate" and "predictable".
His forthright views have also not helped Gatland's chances of achieving his oft-repeated ambition of returning to New Zealand one day and becoming All Blacks coach.
He referred to the possibility as recently as last month, telling British media he wanted to go to the 2019 World Cup with Wales but it would be "fantastic" to take over the reigning world champions at some stage.
Gatland left New Zealand to pursue his coaching career in 1996 and has been overseas ever since, barring a stint back in Waikato from 2005-07.
He has a creditable coaching record, leading the Lions to victory over Australia in 2013, winning three Six Nations titles with Wales and enjoying success at club level.
But it's not a CV that would have the All Blacks swooning as they look to build on back-to-back world titles and an unprecedented 90 percent win rate.
New Zealand Rugby boss Steve Tew said this month that Gatland was among the expatriate Kiwis who would be considered if Hansen steps down in 2019, even if he's not at the front of his mind.
"Joe [Schmidt] is sitting in Ireland and we'd like to have him back. Vern [Cotter – Montpellier, former Scotland] is coaching at a very high level and you wouldn't rule Gatty out either," Tew said.
Weighing against Gatland is the fact that the All Blacks prefer to promote from within – Hansen served an eight-year apprenticeship under Graham Henry before taking the top job.
That puts current assistant coach Ian Foster in the box seat to succeed Hansen.
Before the series began, All Black great John Kirwan said having a Kiwi like Gatland with an intimate knowledge of New Zealand rugby was an "X-factor" for the Lions as they chase a first series win since 1971.
It has not proved the case so far. The Lions are 0-1 down in the three-Test series and Gatland must produce something special to make a statement in the second clash with the All Blacks in Wellington on Saturday.
That's assuming he has not had a change of heart about his All Black ambitions during the bruising tour of New Zealand.
Gatland retains close links with the homeland and his wife and children still live in his North Island hometown of Hamilton while he plies his trade abroad.
But he has been disillusioned at his reception in New Zealand, complaining about attacks against him in the local media and his "trash talk" exchanges with Hansen.
The coverage includes accusations that Gatland is "unravelling" under the pressure of the tour and a full-page caricature in the New Zealand Herald depicting him as a clown.
"I'm not bothered what [Hansen] says or what a newspaper draws. I hope it was a happy clown, that's all," Gatland responded.
"I'd like to think as a Kiwi that some things about me would be more positive from some media, but that hasn't happened.
"One or two people have had a personal campaign against me, but that's water off a duck's back. I couldn't give a toss."