President-elect Donald Trump, in a statement early this morning, announced his intention to nominate ExxonMobil chairman and CEO Rex Tillerson to lead the State Department and become the country's top diplomat.

The selection, which had been rumored for the past week, is unusual in a number of ways, and could face more scrutiny than usual when the Senate holds confirmation hearings.

Here are some key facts about the president-elect's nominee for the final major position to be filled in his Cabinet:

Tillerson never has worked for the government — or anyone other than Exxon since 1975

Tillerson is the Wichita Falls, Texas-born son of a Boy Scouts of America administrator who rose to become an Eagle Scout himself, Steve Coll told NPR's Michel Martin. He joined Exxon Co., U.S.A. shortly after earning a Bachelor of Science degree in civil engineering from the University of Texas at Austin.

He never left, working his way up through the ranks to eventually lead the company.

The selection of a private-sector executive as secretary of state has happened before, The Wall Street Journal notes, with Bechtel executive George Shultz serving under Reagan — but Shultz had previously served as secretary of labor and Treasury secretary.

Still, Coll notes in a New Yorker piece that the oil giant runs a very State Department-like team of analysts that predicts which countries will remain stable enough to ensure profitable investment. And The Washington Post's Philip Rucker reported late Monday that Tillerson came with recommendations from former Secretary of Defense Robert Gates and former Secretary of State Condoleezza Rice.

Council on Foreign Relations president Richard Haass told NPR's David Greene that the selection could work, with the right support.

"There's some difference between knowing about the world and knowing about foreign policy," Haass said. "He'd obviously need to surround himself with people who had experience on the ground inside the department and around the inter-agency process."

He's had extensive dealings with Russia — which may complicate his confirmation

Tillerson spent much of his ExxonMobil career in the company's international division, Coll told NPR, developing ties to countries around the world — particularly Russia.

"That brought him into contact with Vladimir Putin," Coll said. "ExxonMobil is one of the few American oil companies that has managed to stay in Russia through all kinds of political weather."

Tillerson developed close ties to state-run oil company Rosneft, NPR's Lucian Kim reports, and had reached agreements to run development projects with Rosneft in Siberia and the Russian Arctic. Those projects came to a halt when the U.S. imposed economic sanctions following Russia's annexation of Crimea in 2014. But the agreements left him with a good reputation in the country.

" 'The Russians respect strength, and they see it in ExxonMobil and Rex Tillerson. They like him,' Edward Verona, a former ExxonMobil Russia vice president, told NPR. 'Putin likes that personality type — not exactly the Trump personality, but the personality that quietly projects power, discipline, control. ... It's a pretty good example of diplomacy, alliance-building, seeing who your friends are and what they can do for you. It was pretty shrewd deal-making.' "

Following CIA allegations of Russian hacking to benefit Trump during the 2016 presidential campaign, Tillerson will have to explain those ties to senators if he's to be confirmed, CFR's Haass told NPR.

"He would have to say, 'Here's why I did what I did at the time. Here's how I'm going to separate myself from it now. Here's how I view Russia and how I would approach policy toward Russia.' So this is now probably the biggest single set of questions he would have to tackle."

The diplomatic goals of Tillerson's company haven't always lined up with those of his government

The post-Crimea sanctions were not the first time ExxonMobil's goals were at cross-purposes with those of the United States, Coll told NPR.

"ExxonMobil is a very large corporation that really sees itself as an independent sovereign in the world. It has revenue the size of the economy of South Africa. It operates all over the world, negotiating with leaders on behalf of its shareholders. It's kind of a parallel quasi-state."

Exxon operates in more than 50 different countries, The New York Times reports; Tillerson became an important figure in nations around the world, Coll wrote in The New Yorker. He offered the example of ExxonMobil's business activity in the African nation of Chad:

"During the mid-two-thousands, the entirety of U.S. aid and military spending in the country directed through the U.S. Embassy in the capital, N'Djamena, amounted to less than twenty million dollars annually, whereas the royalty payments Exxon made to the government as part of an oil-production agreement were north of five hundred million dollars. Idriss Déby, the authoritarian President of Chad, did not need a calculator to understand that Rex Tillerson was more important to his future than the U.S. Secretary of State."In Kurdistan, during the Obama Administration, Tillerson defied State Department policy and cut an independent oil deal with the Kurdish Regional Government, undermining the national Iraqi government in Baghdad. ExxonMobil did not ask permission. After the fact, Tillerson arranged a conference call with State Department officials and explained his actions, according to my sources, by saying, 'I had to do what was best for my shareholders.' "Copyright 2016 NPR. To see more, visit http://www.npr.org/.