SIMI VALLEY / SAN JOSE, CALIFORNIA - When the Vietnam War ended in 1975, and the first refugees trickled into the Los Angeles area, Helene Ross, co-founder of the Westlake Women's Club, organized the group to collect necessities and distribute them to displaced Vietnamese.

Kieu Hoang accepted clothing and, later, household goods and a motorbike.

In September, he gave $5 million to help Houstonians rebuild after Hurricane Harvey. "I come here to thank the American people who allowed us to come to this country as a refugee in early 1975," he said at a press conference with Houston Mayor Sylvester Turner.

Mayor @SylvesterTurner accepts gracious donation from Hoàng Kiều $5M to hurricane #Harvey relief fund https://t.co/dmgCGBK3Cz — City of Houston (@HoustonTX) September 11, 2017

In March, he gave $5 million to help flood victims in San Jose, where dam overspill forced 14,000 people to evacuate. Many of them, immigrants from Latin America and Vietnam, are among the city's poorest.

"Kieu was very clear," said San Jose Mayor Sam Liccardo of Kieu's no-strings-attached directive. "Every dollar was to go to those who are struggling to get back home. So, his mandate was clear and it was perfect. It was exactly what we needed."

Helene Ross, now 91, said she never thought the young Vietnamese refugee she helped would become an entrepreneur helping others on such a scale.

"Not in a million years," she said.

Hoang, now worth $2.8 billion according to Forbes magazine, owns a sushi restaurant, an eponymously named Napa Valley vineyard, a nutritional supplements company, and a $33 million ranch called Hummingbird Nest which is a short drive from Westlake Village. The ranch earns its keep — "a spectacular site for special events including weddings, private parties, movie/tv and photo shoots," says the website.

"If you want to reach your dream, you have to work hard," Hoang said. "If you want to have money, you have … to figure out how to make money."

Working for a dream

In his early days in California, Hoang, the father of five, worked three jobs.

He realized there was money to be made selling rau ram — a Vietnamese herb also known as Vietnamese cilantro or Vietnamese coriander — growing in a friend's backyard.

WATCH: Vietnamese Refugees

Hoang bought rau ram low, then rode his motorbike to sell high to markets in areas where Vietnamese refugees like himself had settled.

"That is how I made money and grew it," said Hoang, adding that bundling herbs for market built on survival skills he picked up while working as a combat interpreter for U.S. Special Forces during the Vietnam War.

"When we were dropped off in the jungle, that was it," said Hoang, who volunteered with the U.S. military after spending a year studying science in college. "Nobody could come to rescue you. You had to find a way to survive."

Hoang's survival in the U.S. hinged on Ross' group, which with the United Methodist Church of Westlake Village, sponsored him after he left Saigon, as Ho Chi Minh City was then known, days after North Vietnamese forces occupied the capital of the defeated South in 1975.

"They didn't have a place to live, a job, friends, or clothing," said Ross. "So we found an apartment quickly for them, paid the first and last month's rent, so that they could move in immediately."

She remembers Hoang and his family, their eagerness to start a new life.

'Bloody business'

A church member who worked at Abbott Reference Laboratories recruited Hoang in 1975 for an entry-level position paying $1.25 per hour. He promised to overcome his lack of experience by working hard, and kept that vow by clocking 12-hour days.

Within six months, Hoang was a supervisor, the first rung on a ladder that led to becoming director of the company's blood plasma testing and manufacturing division. He remains proud of his work testing plasma.

Five years after resettling in the U.S., Hoang struck out on his own, founding his own plasma lab, Rare Antibody Antigen Supply Inc. (RAAS). By 1985, RAAS had 11 U.S. locations, and was, he said, approved by the state of California to begin testing for HIV in blood samples and plasma. By 1992, he expanded into China, where he established Shanghai RAAS Blood Products Co.

The company introduced new technology into China, that "created the Chinese plasma business de novo," said Dr. Lucy Reynolds, a research fellow and the co-director of the Master's program in Control of Infectious Diseases at the London School of Hygiene and Tropical Medicine.

Billionaire Kieu Hoang, a former refugee from Viet Billionaire Kieu Hoang, a former refugee from Vietnam, says what he wants most is to help the most vulnerable people, rather than having his name put on prominent buildings. Billionaire Kieu Hoang, a former refugee from Vietnam, says what he wants most is to help the most vulnerable people, rather than having his name put on prominent buildings.

The company launched just before some of China's supply of donated blood was found to be contaminated with HIV and hepatitis. The scandal drew international attention as donors — whose blood was drawn with infected needles — and recipients died.

Hoang and Shanghai RAAS Blood Products Co. were never implicated, and Forbes ranks the company fourth in its Innovative Companies list.

According to Forbes, as of October, Shanghai RAAS has a market capitalization of $14.5 billion. Hoang owns 37 percent of the company.

"In this kind of bloody business, we have competition everywhere," he said, alleging his competitors tried to discredit him. "They try to say our product is bad. This and that China product, so this is the kind of thing I tell you. I hate it."

Embracing philanthropy

Still, Hoang remains vice chairman of Shanghai RAAS, as he embraces philanthropy.

"I cannot eat three bowls of rice at one time," Hoang said of his gifts to those rebuilding in San Jose and Harvey.

"I cannot wear two pairs of shoes at one time. So all of my money, I give some to my children, some for my key employees and the rest will serve all those kinds of purpose," said Hoang.

Kieu Hoang, a former refugee from Vietnam, overcam Kieu Hoang, a former refugee from Vietnam, overcame challenges and difficulties to successfully resettle in his adopted country. (Photo courtesy of Kieu Hoang) Kieu Hoang, a former refugee from Vietnam, overcame challenges and difficulties to successfully resettle in his adopted country. (Photo courtesy of Kieu Hoang)

He is known in Vietnam for his love affair with a lingerie model and for his flamboyant style, exemplified by his green Gucci suit adorned with bees and stars. But the billionaire said he is keen on helping the most vulnerable people, rather than having his name put on prominent buildings.

"Doing all these things so you can have a name forever, that is not what I want to do when people indeed need help badly," he said.

Lindsey Caldwell, Catholic Charities division director for disaster recovery services, dispersed some of the money Hoang donated after the San Jose flooding, using it for temporary housing, car repairs, household items, tools that people needed for their jobs and even food.

Elizabeth Arredondo, who with her family was flooded out of her San Jose home, lost everything but important papers stored high in a second-floor closet. She is one of the beneficiaries.

"It gives me much joy that a person like him took interest in what happened to us," she said, adding that Hoang "has a really good heart."

"That large donation really impacted the community in positive ways beyond measure," Caldwell said. That an immigrant helped so many immigrant families "is a beautiful picture of what the United States is made up of."

Dreaming another dream

As a former refugee who overcame challenges and difficulties to successfully resettle in the adopted country, Hoang said he had "a dream to have immigration laws [in the U.S.] so that a lot of people do not live in constant fear of being deported."

He hopes the potential laws "can attract good people like me to help America to be greater and the greatest."

Immigration has become one of the key issues under the Trump administration as the White House said last month that it wanted to, among other things, "defend the safety and security of our country; and protect American workers and taxpayers."

"I call on anybody who makes a decision and who has a conscience to vote, to think about where their ancestors came from and how the United States of America was formed. And when you look at all the successful stories of all the people who contribute to the country, who are they? They have to remember that," Hoang said when asked about his message to President Donald Trump.

On November 5, Hoang was among an audience of 500 who listened to Ivanka Trump, assistant to the president, and Treasury Secretary Steven Mnuchin as they "explained to us the details of tax reform."

Vietnamese-American entrepreneur Kieu Hoang meets Vietnamese-American entrepreneur Kieu Hoang meets with Ivanka Trump, senior adviser to her father, President Donald Trump. Hoang has donated $10 million to help Harvey and California flooding victims rebuild. (Photo courtesy of The Ronald Reagan Presidential Foundation and Institute) Vietnamese-American entrepreneur Kieu Hoang meets with Ivanka Trump, senior adviser to her father, President Donald Trump. Hoang has donated $10 million to help Harvey and California flooding victims rebuild. (Photo courtesy of The Ronald Reagan Presidential Foundation and Institute)

"America will be great again," said Hoang, as companies bring back "trillions and trillions" of dollars that will be "used to invest into this great America."

There are now millions of Vietnamese Americans living in the U.S., making them the largest overseas Vietnamese community in the world.

Hundreds of thousands of Vietnamese fled after the Vietnam War, and many of them took risky trips by boats. Hoang's family left Ho Chi Minh City on April 22, 1975, Hoang said, and he was flown out of the country on an American rescue aircraft on April 24. The family re-united on Guam, and flew to Camp Pendleton in Oceanside, California, on April 27. They did not, he said, "suffer as much as boat people."

In a small post office in Little Saigon in California, dubbed "the capital of the Vietnamese refugees," Luong Ngo said he came to the United States when he was 30 years old, roughly at the same age like Hoang, and the 73-year-old former refugee's rags-to-riches story has inspired him.

"He set an example for everyone. If I were billionaire like him, I would also help my community," Ngo said. "It is a way to reflect on the difficult past."