The 145-page citizenship application file, explaining what exceptional circumstances underlay the unusual award, was released last night after a nearly a week of repeated delays by the Department of Internal Affairs.
The file chronicled official concern that Thiel failed to meet residency requirements - acknowledging he did not live in New Zealand, nor did he intend to in the future - but came down in official favour of the application after being convinced of his "exceptional" abilities in entrepreneurship and philanthropy.
Thiel, worth $3.7 billion according to Forbes, became famous for co-founding PayPal, rich from investing early in Facebook, and has invested tens of millions of dollars in local businesses.
His application for citizenship was supported by letters of reference from prominent technology industry locals - and business partners of Thiel's - Sam Morgan and Rod Drury.
In a personal letter Thiel, who also held German and United States citizenship at the time of his application, was effusive about New Zealand.
"I am happy to say categorically that I have found no other country that aligns more with my view of the future than New Zealand," he wrote.
Guy, who signed the application off in June 2011 and also corresponded with Thiel's lawyers in the months following the filing of the initial application in December 2010, said last week he couldn't recall the case.
Lees-Galloway pointed to a cascade of unusual factors surrounding the case, ranging from fewer than one percent of applications requiring a ministerial waiver of under the "exceptional circumstances" clause of the Citizenship Act, to only one in eight - one a fortnight - being eventually signed off.
The department said fewer than one in a thousand citizenship ceremonies took place in a private ceremony overseas, as Thiel's did in August 2011 at the New Zealand consulate in Santa Monica.
"I cannot believe that Nathan Guy could not recall this case. It's very unusual, involving a very high-profile individual."
Last night a spokesman for Guy said; "He stands by what he said."
In a press conference at the Karaka Sale on Monday Guy said he had reviewed the file and said his decision was the right one. "The decision was backed by officials," he said.
How it unfolded
• 1995: Thiel first visits New Zealand. He visits a total four times before applying for citizenship.
• 22 October 2010: Invests $4 million into local company Xero and joins their advisory board.
• 12 December 2010: Makes formal application for citizenship.
• 20 April 2011: Christchurch Earthquake Appeal Trust announced Thiel has made a $1m donation.
• 30 June 2011: Thiel's citizenship application is signed off by then Internal Affairs minister Nathan Guy.
• 12 August 2011: Private citizenship ceremony take place for Thiel in Santa Monica.
• 25 Jan 2017: News of Citizen Thiel breaks in the New Zealand Herald.