HO CHI MINH CITY -- "We spent everything to get the family to the U.S., and now you're going to back?!" Esther Nguyen's mother made her feelings abundantly clear when she heard of her daughter's plans to set up shop in the old country.

Esther is part of a growing number of young Viet Kieu, or overseas Vietnamese, now playing a vital role in the country's growth.

For the most part, they are the children of first-generation immigrants who fled the Vietnam War, but now see their parents' former home as a new land of opportunity.

Typically armed with expertise and education from their country of birth, many serve as a bridge between local and foreign companies seeking to expand in the Vietnamese market.

Nguyen, is the founder and CEO of Pops Worldwide, a music content management and distribution company in Ho Chi Minh City. The office has a bright, modern feel, with young employees in casual clothes.

"My baby will be born in November in Vietnam. I can't take too much time away from here," said Nguyen. "If I go back to the U.S., it takes two month before, and three-four months after the birth. I can't be away for six months while the company is growing so fast. It's too long!" she said with a smile.

Esther was born in Michigan and raised on the Bay Area. Her parents had fled to the U.S. when what was then Saigon fell in 1975. In their new home, they operated a gas station and mini-market. "It is a typical American success story," she said.

After graduating from the University of Southern California in 1998, she began selling cosmetics online, then went into green technology, but neither venture proved successful. She went on to earn a law degree at Golden Gate University.

Even so, Nguyen never lost the entrepreneurial itch and in 2007, decided to leave the U.S. for Vietnam. While working for an IT company she occasionally visited a developer center in Hanoi and realized the huge opportunities her parents' birthplace had to offer.

Unperturbed by her mother's opposition and inspired by the music streaming services that had just launched in the U.S., Nguyen was determined to use her legal knowledge and Silicon Valley experience to set up a copyright protection business for music and entertainment content.

Few took her seriously at first, but a dramatic increase in smartphone use boosted demand for video content. Having seen the opportunity first, Pops Worldwide now owns around 90% of the music content in Vietnam and boasts total monthly views of 1.2 billion.

As a returnee, she is also adept at coping with the differences between the two cultures. "I came from Silicon Valley, where everything moves very fast," she pointed out. "Vietnam is not so much like that. Things take more time -- a lot more time. And the experience level is also very different."

A long way to go

500 Startups Vietnam partner Eddie Thai

Eddie Thai, a partner at venture capital company 500 Startups Vietnam, graduated from Harvard before starting out at a U.S. consulting company. But despite the salary and prestige, he felt there was something missing.

Recalling a trip to Vietnam as a teenager in 2001, he said, "It was very impressive," but felt Vietnam "has long way to go in terms of improving economic opportunity and standards of living."

At the time he imagined perhaps one day retiring in the country his parents left. But frustrated in his work and keen to have an impact on how people lived, it dawned on him that Vietnam offered him the opportunity he was looking for.

Thai is now responsible for managing a fund of $10 million. "I am considering investing in more than 100 companies, mostly in the so-called fintech, E-commerce, or Education sectors within a few years, because Vietnam has a large pool of skilled engineers," he said confidently.

One of the key strengths Vietnamese-Americans have lies in connections to the U.S. business community. "Having a combination of Western business ethics and a trusted U.S. brand [like Harvard] may make it easier for me to develop trust with potential international business partners."

Many have been described as playing the "pilot" role in helping U.S businesses expand their foothold in the country. In 2014, McDonald's chose Vietnamese-American Henry Nguyen, who heads IDG Ventures Vietnam, as its first local franchise partner.

Also a Harvard graduate, he is the son-in-law of former Prime Minister Nguyen Tan Dung and is a hugely influential business figure.

Henry said "I think that Viet Kieu can serve the bridge between foreign company and Vietnamese side. They have different expertise and experience, compared with local people. I do believe that they have a significant impact on Vietnamese economy".During a three-day visit to Vietnam, U.S. President Barack Obama told entrepreneurs, "We're seeing Vietnamese-Americans who are coming here to start new ventures -- and that shows a strong bond between the United States and Vietnam."

With economic ties between the two countries poised to deepen further with the Trans-Pacific Partnership agreement, many young returnees appear unburdened by the weight of history.

"I am not inheriting the psychological scars of war," said Phan Kim Don, who operates online baby products store TaEmBe.com.

For the older generation, however, the trauma is still very real. Trung Dung, the 49-year-old CEO of iCare Benefits, remembers life as a refugee in the 1970's. "As we were very poor in Vietnam, we made a living selling the trash we picked up off the street to recycling companies," he recalled.

After living in refugee camps in Indonesia and elsewhere, his family eventually made it to the U.S. in 1985. "My first job was cleaning toilets in a hospital," he said. With great difficulty, he earned a computer science and mathematics degree from Boston University, and got a job at an IT company.

In 1996, Dung set up OnDisplay and took the software development company public on the Nasdaq stock exchange the following year. In 2000, he earned approximately $1.8 billion from its sale.

"Although I initially had no intention of returning to Vietnam due to distressing wartime experiences, I felt that something should be done for our ancestral country," Dung said. In 2007, he founded iCare Benefits in the country, which began to provide an "employee benefits program" for corporate customers. Under the program, even low-income factory workers gain access to smartphones and electrical appliances through interest-free installment plans.

Roughly 900 Vietnamese companies use the program, and plans are being made to roll out in other parts of Southeast Asia and India.

The influx of overseas Vietnamese indicates how the government wishes to harness the strength and experience of the diaspora as a tool for economic growth. According to the World Bank, the amount of remittance from overseas Vietnamese to the country reached about $13.2 billion in 2015, a fourfold increase over the last decade.

Only time will tell what long-term impact Viet Kieu will have on this rapidly developing economy. But for many like Esther Nguyen and Eddie the land their parents fled presents a huge opportunity.

Nikkei staff writer Marimi Kishihmoto contributed to this report.