Mr Tillerson, 64, won approval in a remarkably close vote, 56 to 43, the most contentious vote for the top diplomat in modern US history. Two of the more controversial Secretary of State picks in the past few decades, Henry Kissinger and Condoleezza Rice, made it through confirmation with significantly wider margins than Mr Tillerson – 78 to 7 for former; 85 to 13 for the latter.
The 69th Secretary of State, Mr Tillerson is now charged with promoting President Donald Trump's so-called "America First" policy across the globe, as international leaders express concern worry the President's clamorous approach to foreign policy-via-Twitter.
"Tillerson faces the most difficult task of any Secretary of State in the postwar era in trying to reconcile President Trump’s intention to make a radical break from decades of bipartisan consensus US foreign policy leadership," Ryan C Crocker, a former US ambassador, told the New York Times, "with the reality that, if he succeeds, such a break could lead to global chaos."
His confirmation also comes as roughly 1,000 career diplomats expressed their disapproval of Mr Trump's executive order to temporarily halt travel from seven majority-Muslim countries on the unsubstantiated belief that it will keep the country safe from terrorism.
'This ban … will not achieve its stated aim to protect the American people from terrorist attacks by foreign nationals admitted to the United States,” the dissent memo reads.
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It adds: "[The ban] will immediately sour relations with these … countries, as well as much of the Muslim world, which sees the ban as religiously motivated."
But the White House made clear, in response to the dissent memo, that State Department employees who fail to agree with the Trump administration are free to leave their posts.
"Obviously we’re aware of the [dissent memo], but I think that any government official who doesn’t understand the President’s goals in this and exactly what it was," Press Secretary Sean Spicer told reporters, "they should either get with the programme or they can go."
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Still, Tillerson does not quell concerns over national security, especially as it relations to the Trump administration's relationship with Russia.
In the final days of the Obama administration, intelligence officials published a report that concluded the Kremlin backed a campaign to hack the Democratic National Committee to release information that would sway the US election in Mr Trump's favour. While the President has conceded that Russia was the likely culprit behind the cyber attack, he has insisted on fostering a good relationship with President Vladimir Putin.
Additionally, Mr Trump has said he was open to lifting sanctions imposed on Russia in 2014 for their illegal annexation of Ukraine's Crimea peninsula – which could directly benefit ExxonMobil, as Mr Tillerson brokered $500bn (£409bn) energy partnership with the country.
As a result, he was awarded the Order of Friendship from the Russian president, the highest honour a foreign national can receive in the country.
But ExxonMobil had to cease operations in the region in 2014 because of the sanctions – which Mr Tillerson opposed at the time. The head of the oil giant’s Russian operations, Glenn Waller, said the company would return to the project once sanctions had been lifted.
Mr Tillerson said there should have been a military response to Russia in 2014, and their aggression toward the Ukraine resulted from an "absence of American leadership".
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