And there he was again the next morning, filing into the West Wing with Trump and assuming the same position, directly on the President's shoulder. If he'd wanted to, he could've leaned forward and whispered sweet nothings into Trump's ear.
Regardless of what you think of his boss, Liddell's professional journey from Matamata to the White House makes for an incredible career progression.
From his early days as the boss of Carter Holt Harvey and New Zealand Rugby, to his time as the CFO of Microsoft and General Motors, his current gig will be considered by many of his contemporaries his most prestigious appointment to date.
But this is the age of Trump and Liddell's new role will not be celebrated as it would have been with any other President. Many Kiwis will consider that in accepting the job, Liddell made a pact with the devil.
I've spent only a little time with Liddell, but have been left with the impression of supreme competence and confidence.
I interviewed him last year on a couple of occasions, including for an extended political discussion during the US primary campaign near Liddell's former office in central Manhattan.
Liddell told me that days after Trump announced his candidacy he'd made a bet at a dinner party and picked the now-President's successful ascension.
He was careful in my interview not to broadly criticise candidate Trump. The world might have been surprised when Trump became President, but Liddell was not.
Later, we spoke again during one of Liddell's regular journeys home. As head of the Next Foundation, he'd just announced his ambitions for a predator-free New Zealand.
The incredible philanthropic work strikes an alarming moral contrast with Liddell's new role.
How can a committed environmentalist take a job with a President who tells the world that climate change is a hoax?
For a moment, try and imagine it. Put yourself in Liddell's shoes.
Keep in mind that Trump regularly ignores the advice of his advisers. Is it better to take a moral stand and refuse to work with a demagogic leader, or to try and enable positive change from inside the belly of a beast?
Should Liddell have refused the President's job, or should he use his role to try and steer Donald Trump towards positive change?
Already, Trump has revived construction of the Keystone XL Pipeline, connecting Canada's oil sands with refineries in the US. Burning the oil will guarantee the release of catastrophic quantities of carbon. I can't imagine that sitting well with anyone who dreams of a predator-free New Zealand.
The answer to this quandary will lie in Liddell's results. If he does little more than enable Trump's most hateful policies, his role in the administration will make for a massive moral stain on an otherwise glittering career.
Perhaps, though, he can use his position to quietly bring the President about. If Liddell stops the next Keystone XL or convinces Trump to scrap coal, he will achieve more good than a moral stand ever would have.
