NEW YORK • As chief of ExxonMobil, Mr Rex Tillerson honed many of the skills inseparable from the exercise of high-level diplomacy: navigating complex geopolitics and pushing tough negotiations with friends and foes around the world.
The question now facing the 64-year-old Texan, as President-elect Donald Trump's nominee for Secretary of State, is whether he can bring those skills to serve American interests, and break free from the oil industry that shaped him over a lifetime.
As Mr Trump himself put it, in announcing his choice of the chief executive for top diplomat last Tuesday, "his relationships with leaders all over the world are second to none". One of those relationships - with Mr Vladimir Putin, who awarded him Russia's Order of Friendship in 2013 - was likely a key asset in Mr Trump's view, as he pushes for a detente with Moscow.
But Mr Tillerson's Russia ties have raised hackles across the United States' political spectrum, and threaten to severely complicate his approval by the Senate, against the backdrop of intelligence indicating that Moscow had tried to sway the election for Mr Trump.
Senator John McCain was among those voicing concern. "Vladimir Putin is a thug, bully and a murderer, and anybody else who describes him as anything else is lying," he said ahead of Mr Tillerson's nomination.
And if Mr Trump sees Mr Tillerson as a dynamic deal-maker whose contacts are a precious asset for his administration, environmentalists have voiced serious concern at the prospect of an oil industry veteran representing the US in global climate negotiations.
Mr Tillerson joined ExxonMobil in 1975, as a young engineer fresh out of college, and has never worked anywhere else, rising steadily through the ranks to become chief executive in 2006. After a decade spent overseeing the company's business activities in more than 50 countries, he had been due to retire in March.
Mr Steve Coll, author of a 2012 investigative book about ExxonMobil, wrote in The New Yorker that Mr Tillerson's life was profoundly influenced by the oil giant, an organisation that promotes almost all its leaders from within.
Mr Coll describes ExxonMobil as a transnational power independent of the US government, and has its own foreign policy that seeks to create the best conditions for oil and gas production.
In furthering that policy, Mr Tillerson has effectively been "running a parallel quasi-state", "fashioning relationships with foreign leaders that may or may not conform to the interests of the United States government".
But Mr Coll also describes Mr Tillerson's record at ExxonMobil as one of professional integrity.
Among the burning issues awaiting Mr Tillerson beyond Russia are ties with China, the protracted Syrian conflict, Mr Trump's vow to review the Iran nuclear deal and to pull out of both the Trans-Pacific Partnership trade deal and the Paris climate agreement.
Beyond his advocacy for free trade, Mr Tillerson's broader political views are largely unknown. But environmentalists are raising a red flag over ExxonMobil's past activism on the issue of climate change.
"We cannot let Mr Trump name the world's largest oil company in charge of our international climate policy. Mr Tillerson may be a friend of Mr Putin, but he is not a friend of the planet," said environmental group 350.org.