This is one in a seven-part series featuring the major GOP presidential candidates.

WASHINGTON — At 19, Jon Huntsman arrived in Taiwan for a two-year gig as a missionary for the Mormon church. He didn’t receive a warm reception. The Taiwanese government was furious at the United States for re-establishing diplomatic ties with China, and the people whom Huntsman was there to recruit to his faith weren’t much happier.

“You don’t know much of the language at all,” Huntsman recalled of his first days, bunking in a squalid apartment, riding his bicycle by the U.S. Embassy, which had been pelted with tomatoes, eggs and rocks. “You’re in a foreign environment. People are calling you names and spitting at you for reasons that you’re not fully up to speed on.”

Yet the teenage venture would serve as a defining moment for Huntsman. He learned Mandarin and later would return to live in the region three more times, including stints as the U.S. ambassador under Presidents George H.W. Bush and Barack Obama.

“It was such a monumental, geopolitical event happening under my feet,” Huntsman said. “At 19, I was able to see the power and the influence of the U.S. abroad and how it changes history.”

Now 51, Huntsman is running for the Republican nomination for president, touting himself as the only candidate with foreign-policy experience, along with two terms as a popular governor of Utah, one of the country’s most conservative states.

But he’s struggled to break into double digits in polls, and he acknowledges that his decision to cut short his second term as governor and go to China for a Democratic president is a non-starter for “a certain percentage” of hard-core, anti-Obama conservatives.

In addition, his support for civil unions for same-sex couples, as well as what conservative commentators considered a snarky assertion in support of climate change — he tweeted in August that he believes in “evolution and trust scientists on global warming. Call me crazy” — fueled Republican suspicion of his conservative bona fides, which supporters say include state tax cuts, passage of a flat state income tax and an anti-abortion record.

Huntsman and his family say that his decision to serve as U.S. envoy to Beijing wasn’t complicated: The president asked him to serve his country during a crucial time. To counter critics, Huntsman raises the issue before his audiences at campaign events can.

“I know it’s on people’s minds, and I don’t want them left wondering, ‘Why would he serve?’ ” Huntsman said in an interview at his campaign headquarters in New Hampshire, where he’s staking his candidacy. “If the president of another party asks me to stand up, that’s what I’m going to do. I think people relate to putting country before party.”

He positions himself as a candidate of conviction — contrasting himself with fellow Mormon Mitt Romney, whom he portrays in a campaign ad as a wind-up, back-flipping monkey — and says at some appearances that it would’ve been unpatriotic to turn down Obama.

Such public service runs deep in the Huntsman family, one of the most prominent in Utah, friends say. His two sons serve in the military. His father, Jon Huntsman Sr., who made a fortune by inventing the containers that held Big Macs, is a major philanthropist and has said he wants to “to die broke” after donating much of his fortune to cancer research. (Huntsman Sr. also is said to be contributing to an independent political action committee that backs Huntsman).

“Jon very much comes from that cloth,” said Jeff Hartley, a Utah lobbyist and adviser to Huntsman’s gubernatorial campaigns. “It’s genuine.”

Huntsman — the eldest of nine — long has been his own person, friends say. Indeed, he may be the first presidential hopeful in recent history not to graduate from high school. As he tells it, he ended up a class short after “trying to make it big as a musician,” a keyboardist for his teen rock band, Wizard.

A classically trained pianist, Huntsman “could play anything that a rock keyboardist would play and it would sound exactly like it did on the record,” marveled Howard Sharp, a Utah physician who played the drums for Wizard. Huntsman “had the big hair,” Sharp said, but then, as now, he was well-mannered and polite. Indeed, Huntsman kicked off his presidential campaign with a call for civility.

“We had a couple of guys that were wild and crazy, Jon was always a little bit more low-key,” said Sharp, who still catches concerts with Huntsman when they’re both in Salt Lake City.

Huntsman, who had a band as governor and played gigs across the state, said he returned to “normal civilian life” after 18 months with Wizard yielded no sign of stardom.

He got a high school degree at the University of Utah and went on to the University of Pennsylvania. He married his high school sweetheart, Mary Kaye, and the two raised seven children, adopting two girls from China and India. He worked at his father’s chemical company, the Huntsman Corp., as it expanded into Asia, and at 32 he was appointed the U.S. ambassador to Singapore, the youngest envoy in a century.

He was the U.S. trade representative under President George W. Bush, spending much time traveling abroad, when his eldest daughters, then in high school, told him they had a proposal.

“They said, ‘We’d like our dad back. We haven’t seen very much of you,’ ” Huntsman said. They suggested a job closer to home: governor of Utah.

That campaign was a family affair, as everyone piled into Suburbans to make the sell across Utah. It was no sure thing, despite the family name. There were nearly a dozen candidates in the primary and “no guarantee we’d survive,” Huntsman said.

But he persevered. He won the primary and faced Democrat Scott Matheson in the general election. People in Utah still talk about that campaign, Sharp said.

“They never said a disparaging word against each other; cleanest campaign you’ve ever seen,” Sharp said.

That’s the tone Huntsman set out to strike when he opened his presidential bid, but voters have suggested that they’re looking for more fight than he seems to want to offer; he tells audiences he won’t “light his hair on fire.”

“I am who I am,” he told reporters last week. “I’m not going to pander; I’m not going to light my hair on fire. I’m not going to sign those silly pledges like everyone else onstage has signed. I’m not going to a Donald Trump debate. There are just some things I won’t do.”

With the tumult in the race, some prominent conservatives, including columnist George Will, have suggested a second look at Huntsman. Will said that Huntsman’s platform, which includes ending taxes on capital gains and dividends, was the most conservative.

“He’s been that way the whole way through; people are just now seeing it,” said daughter Abby Huntsman, who helps with the press on his campaign. “He’s always been who he says he is, and everything he’s done, he’s been a success.”

This campaign is as much a family effort as his gubernatorial races. His wife often introduces him at events, and his daughters, who campaign with him, have become a Twitter sensation, with a send-up of a Herman Cain ad.

It’s anyone guess, the candidate said, “who gets more YouTube hits: my foreign policy speeches or my daughters’ YouTube videos.”