He has not moderated his messaging at the C.I.A. Five months ago, he called Iran a “despotic theocracy” and “a pernicious empire that is expanding its power and influence across the Middle East.”

In October, he slipped up in discussing the volatile issue of Russia’s interference in the 2016 election, claiming that American intelligence agencies had concluded that the meddling did not affect the outcome. In fact, the agencies did not give an opinion on the effect of the Russian hacking, leaking and propaganda. The agency issued a corrective statement and Mr. Pompeo has not repeated the mistake.

During Mr. Trump’s campaign, Mr. Pompeo publicly welcomed WikiLeaks’ release of Democratic emails hacked and leaked by Russia. But at the C.I.A., he has denounced the group, which published secret documents on the agency’s hacking last year, as “a nonstate hostile intelligence service.”

He has had to juggle some political grenades. When Mr. Trump learned that some American intelligence retirees doubted the evidence that Russia was behind the 2016 hacking, he asked Mr. Pompeo to meet with William E. Binney, a National Security Agency veteran who has championed alternative theories.

That put the C.I.A. director in an awkward spot because the agency had helped gather the evidence pointing at Russia. The two men had a polite meeting, but Mr. Pompeo did not change his view that Russia was responsible.

Representative Adam B. Schiff of California, the top Democrat on the House Intelligence Committee, called his former House colleague “hard-working and intelligent and willing to hear different points of view.” But he added a cautionary note, saying Mr. Pompeo “has not always been willing to stand up to the president, particularly when Trump has questioned the intelligence community’s conclusions on Russia, and we will need the new secretary to be willing to speak hard truths to the president.”

On covert action, though the details of most operations remain secret, Mr. Pompeo has taken an aggressive approach. In Afghanistan, the agency has sent small teams of highly experienced officers and contractors alongside Afghan troops to hunt and kill Taliban militants across the country. This marks a shift for the C.I.A. in Afghanistan, where the agency had primarily focused on Al Qaeda and on helping the Afghan spy services.