Mr Trump’s decision caps a lengthy process that often played out in public and exposed rifts within his transition team. It also sets him up for a potential battle with Congress over confirming Mr Tillerson, who has connections with Russian president Vladimir Putin.
Billionaire property mogul Mr Trump will officially announce Mr Tillerson’s nomination as secretary of state on Tuesday.
The president-elect had moved towards choosing Mr Tillerson after a meeting on Saturday - their second discussion in a week. Mr Trump was said to be drawn to the idea of having an international businessman serve as the nation’s top diplomat.
But the prospect of Mr Tillerson’s nomination sparked immediate concern on Capitol Hill, where politicians are already grappling with intelligence assessments suggesting Russia interfered with the US presidential election to help Mr Trump.
Florida Republican senator Marco Rubio said on Twitter that “being a ‘friend of Vladimir’” was not an attribute he was seeking in a secretary of state.
In a weekend interview with Fox News Sunday, Mr Trump cast Mr Tillerson’s deep relations with Moscow as a selling point.
As oil and gas giant Exxon Mobil’s head, he maintained close ties with Russia and was awarded the Order of Friendship by Mr Putin in 2013, an honour for a foreign citizen.
“A great advantage is he knows many of the players, and he knows them well. He does massive deals in Russia. He does massive deals for the company,” Mr Trump said.
If confirmed by the Senate, Mr Tillerson’s test will be whether his corporate deal-making skills translate into the delicate world of international diplomacy.
He would face immediate challenges in Syria, where a civil war rages on, and in China, given Mr Trump’s recent suggestions that he could take a more aggressive approach to dealing with Beijing.
A native of Wichita Falls, Texas, Mr Tillerson came to Exxon Mobil Corporation as a production engineer from the University of Texas at Austin in 1975 and never left.
Groomed for an executive position, he came up in the rough-and-tumble world of oil production, holding posts in the company’s central United States, Yemen and Russian operations.
Early in the company’s efforts to gain access to Russian market, Mr Tillerson cut a deal with state-owned Rosneft. The neglected post-Soviet company did not have a tremendous amount to offer, but Exxon partnered with it “to be on the same side of the table”, Mr Tillerson said, according to Private Empire, an investigative history of Exxon by reporter Steve Coll.
Mr Tillerson, who became chief executive on January 1 2006, is expected to retire in 2017. His heir apparent, Darren Woods, was put in place a year ago, so there would be virtually no additional disruption to Exxon’s succession plans if Mr Tillerson were to become secretary of state.
Mr Trump’s choice to serve as secretary of state initially appeared to be a toss-up between former New York City mayor Rudy Giuliani and Mitt Romney, the 2012 Republican presidential nominee.
But Mr Giuliani’s prospects fell amid revelations of his overseas business ties and Mr Romney became the source of a fierce fight within the transition team, with some advisers strongly opposed to the prospect of tapping a Republican critical of Mr Trump during the campaign.
Indeed, Mr Romney blasted Mr Trump as a “fraud” during his White House run, but was full of praise for the president-elect after they discussed the State Department post over a private dinner in Manhattan.
Late on Monday, Mr Romney said in a Facebook post that he was honoured to have been considered and his discussions with Mr Trump were “enjoyable and enlightening”.
“I have very high hopes that the new administration will lead the nation to greater strength, prosperity and peace,” Mr Romney wrote.