When David H. Petraeus arrives in September at the CIA’s Langley headquarters, what sort of man will show up to become the intelligence agency’s 20th director, the fourth in the last seven years?

At last week’s Senate confirmation hearing, Petraeus was a uniformed, be-ribboned four-star general whom Sen. John D. Rockefeller IV (D-W.Va.) described as a “kind of a superstar on the military and intellectual force side.” A man who when asked by the Senate Select Committee on Intelligence pre-hearing questionnaire to list honors and awards — including “military decorations, civilian service citations or any other special recognition for outstanding performance or achievement” — referenced 43 medals, 10 badges and 42 awards.

They ran from the sublime (Defense Distinguished Service Medal, Legion of Merit, Bronze Star) to the ridiculous (Barbara Walters’s pick for “Most Fascinating Person of 2010,” GQ’s “Leader of the Year: Right Man, Right Time” in 2008, the London Daily Telegraph’s “Man of the Year and second most influential American Conservative 2007”).

That may turn out to be the old Petraeus. The man who testified projected a different persona, and I expect that’s the person who, as he put it, will be “taking off the uniform that I’ve worn proudly for 37 years to do this job, I think, in the right way.”

Like the good soldier he is, Petraeus has studied the terrain, starting with discussions last year with retiring Defense Secretary Robert M. Gates, a career CIA analyst and former agency director. Gates, who has grown into a superb public servant, hopefully offered lessons from his own checkered rise through the agency and government bureaucracies. Petraeus has followed up with meetings with several former directors and senior officials, including former president George H.W. Bush up at Kennebunkport, Maine.

And he’s received plenty of advice over the transom, so to speak, from retired CIA officers. One mailed memo arrived in a brown paper package addressed to his wife, Holly. It contained a sealed envelop with instructions: “Deliver this to Your Husband.”

Though he admitted he has much to learn about the agency, his written answers to committee questions about observed differences between the cultures of the military and the CIA are worth recording. He described the agency as “more informal and less rank conscious,” and noted that “intellectual rigor and experience tend to trump rank.” With a “flatter chain of command,” he said the CIA “tends to give its officers somewhat more discretionary authority, especially in the field,” where 25 percent of them reside.

Petraeus also pointed out the low attrition rate at CIA, where “employees stay on board for 25 years ore more.” In the military, roughly 70 percent leave before serving the 20 years needed for retirement.

His past experiences and recent conversations with CIA Deputy Director Michael J. Morrell (who will serve as interim agency head) and other senior officials also have introduced him to the varied cultures within the organization. Clandestine officers who recruit agents and manage covert operations are different from analysts who sift through data and produce analyses. Both, he said, have a “can-do” spirit that permeates through the agency.

In an electric exchange with Sen. Carl Levin (D-Mich.), Petraeus explained his strongly held view on when a commander (or perhaps a past or future CIA director) should or would resign when he disagrees with a presidential decision. Levin raised a hypothetical question based on a president ordering him to do something “you couldn’t do . . . consistent with that [constitutional] oath. You would resign?”

“I’m not a quitter,” Petraeus responded. “I don’t think that it is the place for a commander to actually consider that kind of step unless you are in a very, very dire situation.” He added this important view: “Our troopers don’t get to quit, and I don’t think that commanders should contemplate that as any kind of idle action.”

He said for commanders this should not be done just in protest because “this is not about me, it’s not about an individual commander, it’s not about a reputation. This is about our country, and the best step for our country, with the commander in chief having made a decision, is to execute that decision to the very best of our ability.”

Reading those words I remembered listening fairly recently to a former senior CIA official involved in the waterboarding episodes explain to a group about the mood of fear in the country post-Sept. 11. The CIA was given a direct presidential order for the activity, and more than one legal opinion demanded by agency leaders from the attorney general each time said that the orders were within the law.

Petraeus himself recognized last week that this is still a major morale issue at CIA, because it is not the first time that CIA officers were being investigated for what they did under orders from a previous president of a different political party. He made reference to the criminal investigations still underway into those Bush era events and said today, 10 years later, people don’t “appreciate the context of the post-Sept. 11 period and some actions that were taking place under direction.”

“As the potential leader of the agency,” he added, “I would like to see us focus forward and indeed put some of these actions behind us once and for all and put our workforce at rest with respect to that.”

That is the man who will step out of a car, alone and in civilian clothes, at Langley in September.