Stewart in Cumbria, where he recently became an M.P. “Thirty years of my life will be here,” he said. Photograph by Perry Ogden

“There’s a part of me that makes me a little bit sick,” Rory Stewart said, sitting in the courtyard of an annex of the House of Commons, in London. It was a bright day in July; Stewart had just been elected to Parliament, in an almost casual way, having already passed through many of the key institutions of the British establishment, including Eton College, the Army, Oxford University, and the Foreign Office. Stewart, who memorized “The Waste Land” when he was fourteen—“because I was a very pretentious fourteen-year-old boy”—is now thirty-seven. He has walked thousands of miles across Asia, largely alone, and written two well-received books; the Times called “The Places in Between,” about the Afghan part of his walk, a “flat-out masterpiece.” He has taught at Harvard about war and intervention and become friends with the Prince of Wales; many people think he’s likely to become Foreign Secretary or even Prime Minister. “If I go to a grand reception where lots of people are being polite to me, I’m sort of exhilarated for a bit, but then sick,” Stewart said. He grimaced, his teeth showing, and held the expression until he looked like a sky diver. He said that he saw himself in the eyes of bridegrooms on their wedding day: “You can see that they’re not quite happy.”

Stewart’s words carried an echo of T. E. Lawrence, an idol of his, who once wrote of himself, “There was a craving to be famous; and a horror of being known to like being known.” Stewart’s identification with Lawrence is intense, which is “odder than it seems, because it’s almost too obvious,” his close friend Felix Martin, a British economist, says. Stewart is self-conscious about how easily he inspires confidence and how pleasurable esteem can be. One senses his anxiety: if a man is going to be admired, then let it be for a cause. Stewart, whose manner marks him immediately to the British as someone with ruling-class roots, longs to be more than an ordinary overachiever: he wants to be connected to the epic. He encourages the thought that he is unmoored from the modern age. At college, he used to regret being born into the wrong century. This persona, even when leavened with self-mockery, strikes some as insufferable, but it gives him an exceptional air. His name seems nude without a “Sir” in front of it. When he stands still, he seems to be posing for a sculptor.

A senior M.P. told me that Westminster had not seen such an original and exotic arrival in decades, perhaps since that of Winston Churchill. He then added that “Britain no longer has an empire to run” and has little need for “latter-day T. E. Lawrences acting as cavaliers seuls on the world stage.” In the courtyard, Stewart took off his tie and described a book about heroism that he had tried to write in his twenties: “We imagine, in the modern world, that heroes are accidental heroes.” His enunciation is careful, as if giving street directions to a foreigner. “But, historically, many of the people who were heroes in their society set out to be heroes. They emulated other heroes, were obsessed with being a hero, wanted to be godlike. In contemporary society, that disqualifies you. If you’re trying to be a hero, you almost by definition can’t be. But Achilles wants to be a hero. When he gets grumpy, he says to his mother, ‘You told me that if I agreed to die young and far from home I’d be the best among the best, now and in perpetuity!’ ” (Stewart struck the table in emphasis.) “Then Alexander the Great wants to be Achilles, and has ‘The Best Among the Best’ put above his tent. Caesar wants to be Alexander. Napoleon is obsessed with being Caesar. Byron models his carriage on Napoleon’s, and buys locks of his hair. Lawrence of Arabia travels with the Iliad and ‘Le Morte d’Arthur’ in his backpack. There’s a narrative there, which people aren’t quite taking seriously.” To remain attached to the stories that fill a boy’s dreams is not peculiar or immature: it’s a way to get things done. Stewart had just written and presented a BBC documentary about Lawrence, filmed, in part, in Syria and Iraq. Squinting into the desert, Stewart—lean, straight-backed, and about five feet nine—was never seen without cufflinks, even on camelback.

Stewart reminded me that Lawrence, after his Arabian adventures, renounced celebrity, joining the Royal Air Force at the lowest rank, under a pseudonym: “He ends up with his ‘man’s work.’ He realized he can’t actually be a knight in shining armor.” Stewart added, “You can’t keep going. Look, Alexander’s dead at thirty-three, Byron’s dead at thirty-five, thirty-six. You can’t keep it up forever.” Although Stewart had just been elected to national office—and had just visited Chequers, the Prime Minister’s official country residence, to join a discussion about the future of Afghanistan—he argued that his general trajectory was away from the pursuit of power. In 2003 and 2004, he had helped govern parts of southern Iraq. Between 2005 and 2008, he ran the Turquoise Mountain Foundation, a charity, initiated by Prince Charles, that supports traditional arts in Afghanistan. He then entered academia. “Why would I run an arts school in Kabul?” he said. “It’s not part of the grand narrative. I don’t think Alexander the Great ran an arts school.” He considered for a moment that he had just compared himself to Alexander the Great, and laughed. “If you try to put it down in black and white, the irony vanishes and the monstrous egotism is revealed.”

Fellow-M.P.s passed through the courtyard and stopped to talk. One of them introduced Stewart to a general in the Afghan National Army, and Stewart exchanged greetings in Dari, touching his hand to his chest. A year earlier, Stewart had been newly installed at Harvard, as the director of the Carr Center for Human Rights Policy, at the Kennedy School; his views on Afghanistan and nation-building were sought on op-ed pages and in Washington. In March, 2009, he sat next to Hillary Clinton at a State Department dinner. Now he was one of three hundred and six Conservative M.P.s in a new coalition government—Conservatives and Liberal Democrats—and a chief worry that afternoon was the risk of missing a parliamentary vote if he attended a nearby event promoting British produce. The previous weekend, in the voting district that he represents—in Cumbria, in rural northwest England—Stewart had judged a scarecrow competition. He was feeling uncharacteristically unready, concerned about “this crazy accelerated path, where suddenly, without any of the proper preparation, or any of the things that I believe are necessary conditions for being a politician, I’m suddenly now a politician.”

An added complication is that his views about Afghanistan are not the Conservative Party’s views. The Conservatives, like their opponents in the Labour Party, which was in government between 1997 and 2010, have largely supported American policy in Afghanistan. Stewart believes in a long humanitarian commitment to the country but in a greatly reduced military presence: just ten or twenty thousand troops, so that the Taliban “are at least facing a stalemate,” as he recently put it. He summarizes his stance in a dense sentence that seems to be looking for a place as the epigraph in a future biography: “If we can do less than we pretend, we can do much more than we fear.”

We took the elevator up to his parliamentary office: orange-brown carpet, a wobbly coffee table, a sagging blue sofa beneath a small window. A TV showed proceedings on the floor of the House of Commons. We heard a short speech about taxes on diapers. Stewart watched with an anthropologist’s air. He has faith in his leadership skills—he is decisive, and can carry people with him—and he had been wondering if he could behave more as an executive than as a legislator, a mayor more than an M.P. In Cumbria, he would “manage, pilot, roll things out . . . almost as if I was running an N.G.O.” In this spirit, he had set himself the task of bringing high-speed Internet to his district. That afternoon, he was on the phone with Google, arranging a conference, conscious that it was “a little bizarre” for him, as an M.P., to be negotiating with sponsors and cutting deals. (Stewart’s phone calls end with “Best wishes,” as if concluding a letter.)