Heidi Cruz, wife of Ted Cruz, an intellectual equal, campaign asset

Their first date was at an Austin bar called the Bitter End.

“That’s apropos,” laughed Heidi Cruz, now the wife of Republican presidential candidate Ted Cruz, describing her first date with the senator from Texas who has been surging in the polls in recent weeks.

The dinner lasted several hours, as Mrs. Cruz was peppered with questions from her now-husband, ranging from her spirituality to her 10-year life plan.

At the time, both she and Mr. Cruz were policy aides working for George W. Bush’s 2000 presidential campaign — she on the economic side, he on domestic issues. Friends describe them as intellectual equals — she had just turned down a prestigious job with Goldman Sachs upon graduating from Harvard Business School. He had served as a law clerk to Supreme Court Chief Justice William H. Rehnquist.

“It was certainly a very warm, lively, mutual conversation, and I was intrigued [that] he asked such insightful, deep questions,” said Mrs. Cruz, 43.

That night, like most other nights, she did most of the talking.

“I don’t know that many people recognize what an extraordinary listener Ted is, and you need to be careful on what you say, because he won’t forget a word of it,” she said with a smile.

Fifteen years ago, Mrs. Cruz knew she wanted to be a wife and mother and to work outside of the home, either in public service or business.

Although she has accomplished all of that — juggling a husband with presidential ambitions, her own career goals and the raising of two young daughters — she acknowledges it has proved challenging at times.

Unlike the spouses of many other Republican candidates this election cycle, Mrs. Cruz keeps an active public schedule and has become an integral part of Mr. Cruz’s campaign.

On Monday, Mrs. Cruz hosted multiple events in Missouri, including a rally for the Republican secretary of state candidate in the afternoon and an evening meet-and-greet in Jefferson City. On Tuesday, she will be in Oklahoma to file for the state’s ballot, meet with supporters of her husband and do press interviews. Last week, she was in Virginia and Texas to hold fundraisers, meet voters and file for the two states’ ballots.

Putting in an 18-hour day is not atypical. Neither is spending five nights a week at a Hampton Inn.

“I enjoy my day most when I feel like we’re really getting after it,” Mrs. Cruz said. “My entire desire here is to help Ted win. This is not for me, it’s not for my career, so I don’t feel the stress of that. I’ve always worked, and I’ve always worked 70 or 80 hours a week, so the pace of this does not throw me off.”

Mrs. Cruz is seen as the perfect surrogate for her more outspoken husband on the campaign trail. Where he speaks to large crowds in hyperbolic tones, throwing red meat one-liners that conservative audiences eat up, she comes across as warm and personable, someone eager to show pictures of their two daughters, Caroline, 7, and Catherine, 4, posing proudly next to the small Christmas tree they decorated the prior weekend in the family’s Houston high-rise apartment.

A different kind of conservative

Mrs. Cruz’s brand of conservatism is also different from that of her husband, friends say.

Mr. Cruz is more like Supreme Court Justice Antonin Scalia, hard-nosed and unapologetic, whereas Mrs. Cruz, who served under U.S. Trade Representative Robert Zoellick — who would later serve as head of the World Bank — during her tenure in the Bush administration, is able to reach across the aisle to get things done, said P. Edward Haley, a professor of international strategic studies at Claremont McKenna College and one of Mrs. Cruz’s mentors.

“Ted’s a debater and was groomed to succeed in polarizing and particularizing issues. He’s a hyperbolic speaker, and that’s not quite Heidi,” Mr. Haley said. “My take on Heidi’s politics is she never was as radical as Ted on some of these issues. She’s a businesswoman, a successful businesswoman, and she makes things work. She gets people to talk to each other and doesn’t want to polarize them from the get-go. It’s a different brand of conservatism than her husband’s.”

Still, Mrs. Cruz is solidly in Mr. Cruz’s corner — saying her husband is the only contender in the race who understands the Constitution and has a record defending it. Although businessman Donald Trump remains the front-runner, Mr. Cruz has tapped into an anger that is shared by many Trump supporters that Washington is broken.

Mr. Trump’s campaign and early success have been “useful,” Mrs. Cruz said, “because he has called out issues that the news media was trying to ignore, that people wouldn’t write about, that people wouldn’t put on TV.”

The difference between Mr. Trump and Mr. Cruz is that the senator has a record of taking on Washington insiders and standing up for the values the Texas people voted him into office on — no matter what political capital may be at risk, Mrs. Cruz said. She is betting that Trump voters will eventually gravitate to Mr. Cruz because of this.

“What has Trump done?” Mrs. Cruz asked. “Who has been trying to do something about it?” She cites her husband’s battles — often with his own party leadership — on gun rights, immigration, ending Obamacare, education, religious liberty and federal spending.

“Ted’s exposed the lie, and that’s all there is to it,” she said.

On the campaign trail, Mrs. Cruz has also been working to broaden Mr. Cruz’s appeal, showing a different side of her husband and their life together. She softens him, humanizes him and can appeal to voting bases he’d like to attract but doesn’t always connect with — primarily women and millennials.

“Where I can add value that others can’t is getting voters to know him as a person,” Mrs. Cruz said. “Knowing how thoughtful he is, knowing how he never misses date night, knowing how funny he is, what great wit he has.”

She’s also been a prolific fundraiser, leveraging her experience as an investment banker at Goldman Sachs to close many deals. She has personally made dozens of solicitations a day, targeting Mr. Cruz’s most reliable donors: middle-class business owners.

Mission trips and public service

Mrs. Cruz was born in San Luis Obispo, California, to Seventh-day Adventist missionaries. She traveled as a girl on mission trips to Kenya and Nigeria, and her parents pressed upon her the importance of hard work from a very young age. Mrs. Cruz always knew some sort of public service would be in her life’s calling, and it was a family trip to Washington during the Reagan administration where her passion for politics began.

Mrs. Cruz attended Claremont McKenna College in California as an undergraduate, where she double-majored in economics and international relations, and later graduated Phi Beta Kappa. With help from Mr. Haley, her Claremont McKenna professor, she had mapped out a career that would eventually land her in Washington, working on Wall Street to get the economic expertise to prepare her for public service.

“Heidi was never personally interested in running for office, but she was very interested in public service, so I pointed out to her the classic pattern: First achieve success in private industry, specializing in something specific, so that you would have something to offer that would attract the attention of those making public office appointments,” he said. “Heidi put her head down and did it — she listened.”

Mrs. Cruz started her career on Wall Street, which led to Harvard Business School. Upon graduation, instead of taking the offer at Goldman Sachs, she elected to work on the Bush campaign in order to make the right connections. Sure enough, soon after the campaign, she became an aide to Mr. Zoellick in the trade office.

Her tenacious drive paid dividends. Soon she was promoted as the director of the Western Hemisphere for the National Security Council, reporting directly to Condoleezza Rice — a position she relished.

However, her husband wasn’t having as much success. He was appointed to a position at the Federal Trade Commission, a post that didn’t match his ambitions. When he was offered the position of Texas solicitor general, he jumped at it and moved back to Texas, while Mrs. Cruz stayed in Washington to pursue her dream job.

But the yearlong distance between the two began to take its toll, so Mrs. Cruz quit her job to move to Texas to be with her husband. Soon after moving to the Lone Star State, she feel into a depression.

“The truth is there are different chapters in all of our lives, and the toughest thing about chapters is the transition in between — it’s not always clear what will be next, and that was a tough chapter for me,” Mrs. Cruz said. “I did enjoy what I was doing in the Bush administration, and I’m from California and my family was there, so I had to get my feet under me and start to build a network again, professionally and personally.”

It was her faith, along with help from family and friends, that got her through the dark period.

“I quickly came to see that if I professed to be living not for myself but living for God and others, there might be times that I need to look up and not down and trust that my motivations for moving to Texas were for the right reasons, which were for my marriage. People sometimes say you should not make trade-offs in your life, but I think all successful people make trade-offs,” she said.

In 2005 Mrs. Cruz landed an investment banking job at Goldman Sachs. She rose through the ranks once again to become managing director of the Houston branch, the second-highest position at the firm.

Now she has taken a leave of absence for her husband’s presidential campaign, placing family over career yet again.

But Mrs. Cruz is no martyr — she knows she provides the emotional center of her home, and has taken on her new role within the campaign with as much passion and intensity as her previous work. She serves as wife, mother and as Mr. Cruz’s most trusted political adviser.

Date nights with her husband are every Sunday, usually involve sushi and start no earlier than 10:30 p.m. As far as what they talk about — well, it reflects the varied life the Cruzes are juggling together.

“We talk about everything, from getting the cars repaired to Caroline’s schedule to Christmas gifts, birthday gifts, and then I always have a list of policy questions I want to ask,” Mrs. Cruz said. “So I’ll throw in, ’Should we get the tires fixed or wait?’ and then, ’Hey, by the way, tell me what you really think we should be doing in Syria.’”