He is still that cliche — "boy from Matamata" — after all.
But cue moral outrage down under once his nomination for the secretary-general's role was public.
Liddell is an Assistant to the President and Deputy Chief of Staff for policy co-ordination.
Bold, ruthless and well-connected, he would have drawn on those attributes to both make headway and to survive in the Trump White House.
But he is also extremely competent, which is what his New Zealand critics overlook when they seek to damn him simply because he works at 1600 Pennsylvania Avenue.
In early 2017, I wrote that key to Liddell's success in his White House appointment would be five key factors:
• He puts himself in the "fastest flowing rivers" and is clever about being in the right place at the right time. While other businessmen bad-mouthed Trump he put a successful bet on his victory
• He has bold aspirations and is the kind of guy who is unreasonable about the level of ambition he sets for teams — a necessary attribute given the scope of disruptive change Trump has signalled
• He is extremely focused — takes complex problems, breaks them into parts and makes people responsible for delivering
• He has boundless energy and intellectual curiosity — reads widely and looks for big ideas
• He is comfortable in uncomfortable situations — never the fastest runner in the first five minutes but there when the burn comes on — another useful attribute when Trump's abrasive personality causes friction.
As events turned out, that analysis was on the money.
Prior to assuming his deputy chief of staff role he served as Director of Strategic Initiatives, overseeing the Administration's efforts to streamline the Federal Government's regulatory process and modernise its technology systems. He also had stellar track record behind him.
Before joining the Trump Administration, Liddell served as vice-chairman and chief financial officer at General Motors, where he led global finance operations and managed the company's $23 billion IPO in November 2010, which, at that time was the largest public offering in history.
Liddell has more than three decades of experience in corporate leadership, including as CFO and senior vice-president of Microsoft and CFO of International Paper.
No one gets to the top echelons of US business without major runs on the board.
The US boasts possibly the world's best technological innovation — it is after all the home of Microsoft, Twitter, Facebook, Google et al. But at a governmental level, its IT systems were verging on Neanderthal.
Liddell played a leading role in co-ordinating major investment to modernise the US Government in what has been billed as the "biggest IT transformation of all time".
Even former National Finance Minister Bill English was invited to talk with the data project teams on the leading work New Zealand did on social investment.
Liddell is also a rarity in an Administration where many top members of Trump's Cabinet and White House officials have faced presidential decapitation this term.
But all of this counts for nothing among some NZ politicians who damn anyone who has been in the room with Trump.
Already the Green MPs are in hyper overdrive, fuming at the notion that anyone who had worked at such a high level should be appointed to the OECD top role. Let alone that the New Zealand Government might support his candidacy.
They have displayed a hopeless naivete about how things run in Washington and would rather play the man than the ball.
Liddell is not the first New Zealander to serve in a top-level White House role.
Dr Peter Watson worked for George Bush Snr's Administration as a director of Asian Affairs for the United States National Security Council, and later held top posts in the George W. Bush Administration.
A Republican, he was also appointed chairman of the high-powered US International Trade Commission by the Clinton Administration.
Watson was also a useful back channel for New Zealand, briefing (to the degree possible) NZ ambassadors and visiting politicians on the state of play in the White House.
Liddell also played that role by providing private briefings to then Foreign Minister Winston Peters ahead of his White House meetings with Vice-President Mike Pence. Along with ambassador Scott Brown he paved the way for the Kiwi Act deal opening the door to a new class of trade and investment visas for New Zealanders.
There are two elements which will be critical to his candidacy.
First, OECD members will be wary of supporting a US candidate for this role given the US has pulled back from many multilateral institutions.
Second, Liddell has not been a ranking Cabinet member.
Former European Trade Commissioner Cecilia Malmstrom is considered to be the frontrunner.
New Zealand will also be lobbied by Australia to support their candidate Senator Mathias Cormann.
As Politico notes, the biggest role Liddell could play in the short term is to smooth a possible transition of power after the presidential election.
While Trump refuses to commit to a peaceful transfer of power if he loses, his team (led by Liddell) is "carefully" developing plans for that very outcome.
Politico says the West Wing planning office is one of the most organised and functional parts of the Trump White House.
Another one for the Liddell CV?
