WASHINGTON — President-elect Donald J. Trump on Tuesday officially selected Rex W. Tillerson, the chief executive of Exxon Mobil, to be his secretary of state. In saying he will nominate Mr. Tillerson, the president-elect is dismissing bipartisan concerns that the globe-trotting leader of an energy giant has a too-cozy relationship with Vladimir V. Putin, the president of Russia.
A statement from Mr. Trump’s transition office early Tuesday brought to an end his public and chaotic deliberations over the nation’s top diplomat — a process that at times veered from rewarding Rudolph W. Giuliani, one of his most loyal supporters, to musing about whether Mitt Romney, one of his most outspoken critics, might be forgiven.
Instead, Mr. Trump has decided to risk what looks to be a bruising confirmation fight in the Senate.
In the past several days, Republican and Democratic lawmakers had warned that Mr. Tillerson would face intense scrutiny over his two-decade relationship with Russia, which awarded him its Order of Friendship in 2013, and with Mr. Putin.
The hearings will also put a focus on Exxon Mobil’s business dealings with Moscow. The company has billions of dollars in oil contracts that can go forward only if the United States lifts sanctions against Russia, and Mr. Tillerson’s stake in Russia’s energy industry could create a very blurry line between his interests as an oilman and his role as America’s leading diplomat.
Mr. Tillerson has been publicly skeptical about the sanctions, which have halted some of Exxon Mobil’s biggest projects in Russia, including an agreement with the state oil company to explore and pump in Siberia that could be worth tens of billions of dollars.
Senator John McCain, Republican of Arizona, said on Saturday that Mr. Tillerson’s connections to Mr. Putin were “a matter of concern to me” and promised to examine them closely if he were nominated.
“Vladimir Putin is a thug, bully and a murderer, and anybody else who describes him as anything else is lying,” Mr. McCain said on Fox News.
Mr. Trump has fanned speculation about his choice for secretary of state for weeks. In the end, he discarded not only Mr. Giuliani and Mr. Romney, but also an endlessly changing list that at times included Senator Bob Corker, Republican of Tennessee; David H. Petraeus, the former Army general and C.I.A. director; and Jon M. Huntsman Jr., the former Utah governor and presidential candidate in 2012.
Mr. Romney, Mr. Petraeus and Mr. Corker, the three leading runners-up, all received calls late Monday informing them of Mr. Trump’s decision, according to people familiar with the president-elect’s final choice.
He settled on Mr. Tillerson, a deal maker who has spent the past four decades at Exxon, much of it in search of oil and gas agreements in troubled parts of the world. A native of Wichita Falls, Tex., who speaks with a strong Texas twang, Mr. Tillerson, 64, runs a company with operations in about 50 countries, and has cut deals to expand business in Venezuela, Qatar, Kurdistan and elsewhere.
If confirmed as secretary of state, Mr. Tillerson would face a new challenge: nurturing alliances around the world that are built less on deals and more on diplomacy.
That could prove to be a special test when it comes to Russia, where Mr. Tillerson has fought for years to strengthen connections through business negotiations worth billions of dollars. Under his leadership, Exxon has entered into joint ventures with Rosneft, a Russian-backed oil company, and donated to the country’s health and social programs.
In his new role, Mr. Tillerson would have to manage the difficult relationship between the United States and Mr. Putin’s Russia, including the economic sanctions imposed after Moscow intervened in Ukraine and occupied Crimea. Last month, President Obama and European leaders agreed to keep sanctions in place until Mr. Putin agrees to a cease-fire and to the withdrawal of heavy weapons from front lines in eastern Ukraine.
Other Republicans who have challenged Mr. Tillerson’s potential selection include Senator Marco Rubio of Florida, who expressed concern in a Twitter post on Monday about his relationship with Mr. Putin.
Mr. Trump favored Mr. Giuliani, the former New York mayor, initially, but quickly grew weary of his penchant for drawing outsize media attention. Mr. Trump was also troubled by reports of Mr. Giuliani’s business entanglements overseas. And some of the president-elect’s closest advisers, including his son-in-law, Jared Kushner, saw Mr. Giuliani as a poor fit for the job.
That led to interest in Mr. Romney, who had called Mr. Trump a “fraud” and a “phony” during the campaign. Mr. Romney had also highlighted Russia as a danger to United States interests during the 2012 race.
Mr. Trump and Mr. Romney made peace, meeting twice and speaking periodically by phone. But some of Mr. Trump’s advisers, including his last campaign manager, Kellyanne Conway, warned publicly in a series of television interviews that some of his supporters would quickly drift away if Mr. Romney were chosen for the job.
Mr. Tillerson emerged as a contender on the strong recommendations of James A. Baker III, the secretary of state under President George Bush, and Robert M. Gates, the former defense secretary, according to a person briefed on the process.
Mr. Kushner and Mr. Trump’s chief strategist, Stephen K. Bannon, argued strongly for Mr. Tillerson, and the president-elect was intrigued.
Mr. Trump met with Mr. Tillerson for more than two hours on Saturday at Trump Tower in Manhattan. To his aides, Mr. Trump described Mr. Tillerson as in a different “league” than his other options.
Mr. Romney acknowledged late Monday night in a Facebook post that he had been passed over, writing, “It was an honor to have been considered for Secretary of State of our great country.”
“My discussions with President-elect Trump have been both enjoyable and enlightening,” Mr. Romney wrote.
Michael D. Shear and Maggie Haberman
The New York Times