Born in Moscow, Russia, when it was still part of the Soviet Union, Google co-founder Brin and his family emigrated from the U.S.S.R. when he was just 6 years old. While enrolled in a computer science Ph.D. program at Stanford University, Brin met Larry Page and eventually dropped out to start Google.

Today, Brin is responsible for Google's special projects like Google Glass and self-driving cars. He owns 16% of the company and has an estimated net worth of $24.4 billion.

Chahal's family comes from Punjab, India, where he was born in 1982. He and his family moved to San Jose, California, in 1986 with just $25.

Chahal dropped out of high school at 16 and started his own company, ClickAgent, which he sold for $40 million less than two years later.

BlueLithium, his second company, was bought by Yahoo for a cool $300 million in cash. He's worth more than $100 million today, and has had the opportunity to meet President Obama.

Do Won and Jin Sook, the husband-and-wife team behind Forever 21, didn't always have it easy. After moving to America from Korea in 1981, Do Won had to work as both a janitor and gas station attendant to make ends meet. They opened their first clothing store in 1984.

Forever 21 is now an international, 480-store empire that rakes in around $3 billion in sales a year.

Dham was born in Pune, India, and came to the U.S. in 1975. He was an engineering student with just $8 in his pocket, after refusing to bribe Indian officials for a larger grant. He survived upon his arrival thanks to a loan from the University of Cincinnati's study abroad office.

After graduating, Dham worked for Intel and helped invent Intel's first flash memory chip. He went on to become the CEO of Silicon Spice, which sold for $1.2 billion in 2002.

He is now a venture capitalist, and is looking to give back to his native country.

Born in Hungary, the man originally known as Andras Istvan Grof spent many of his formative years hiding from the Nazis under a false identity. During the Hungarian Revolution of 1956, Grove escaped into Austria and was one of hundreds of thousands of Eastern Europeans who came to America.

Grove arrived in the U.S. in 1957 with little money and even less in the way of English-language skills. He worked as a busboy while studying chemistry at the City College of New York. His English grades were average, but he excelled in all other subjects.

Moving out to California, he co-founded Intel Corporation in 1968. He would later become the company's chairman and CEO in 1997, along the way helping Intel become a billion-dollar company and one of the most important drivers of the information economy. Forbes estimates he's worth $400 million today.

Hawthorne emigrated to the U.S. from Jamaica in 1981 and left behind the family bakery to work for the New York Police Department. He puts it bluntly: "Once I arrived, like most immigrants I had to find employment."

After 10 years of accounting for the NYPD, Hawthorne decided he wanted to return to baking. With no prior business experience, he pooled money from family members (some of whom took out second mortgages to help him) and launched Golden Krust in 1989 in the Bronx.

Today Golden Krust can be found in 125 franchises in nine states along the Eastern seaboard, and grosses more than $100 million in annual sales.

With an estimated net worth of $3.8 billion, Khan is the richest American of Pakistani origin and one of the richest people in the world. But when Khan came to the U.S. from Pakistan, he worked as a dishwasher while attending the University of Illinois. Khan now owns Flex-N-Gate, one of the largest private companies in the U.S., the NFL's Jacksonville Jaguars, and Premier League soccer club Fulham.

The WhatsApp co-founder, 37, was born in Ukraine. He arrived in the U.S. when he was just 16 years old, and his family lived on food stamps.

On Feb. 19, Facebook announced it would buy WhatsApp for a stunning $19 billion in cash and stock. Forbes estimates that Koum holds about a 45% stake in the company, which would make him worth about $6.8 billion. That's a long way from his early days in America.

Ly fled his native country after the U.S. pulled out of Vietnam in 1975. After several failed attempts to escape, Ly lived for nine months in a Malaysian refugee camp before getting assistance from the United States Catholic Charity.

Coming to the U.S. in 1979 with just a dollar to his name, Ly settled in San Francisco. He lived for years with eight other family members in a two-bedroom apartment, learning to speak English as he attended classes.

In 1984, Ly and his four brothers pooled their savings to open the Sugar Bowl Bakery. The bakery saw great success and has expanded to a $400 million dollar business, and in 1993 the Ly Brothers Corporation was born. Ly has been recognized as the Bay Area's "Most Admired CEO" and earned the "Immigrant Heritage Award."

Musk grew up in Pretoria, South Africa, and moved to Canada in 1988 so that it would be easier to emigrate to the U.S. He became a naturalized American citizen in 2002.

Musk made his first fortune when he sold his software company Zip2 to Compaq in 1999 for $22 million. He later made $165 million from the $1.5 billion sale of PayPal to eBay in 2002.

Today, Musk is best known as the CEO and CTO of the private space exploration company SpaceX, as well as the CEO and chief product architect of Tesla Motors.

He has an estimated net worth of $6.7 billion.

Born in Madras, India, the future CEO of PepsiCo grew up conservative and middle-class, studying physics, chemistry, and math. Her determination to study in the U.S. brought her to Yale University's Graduate School of Management in 1978.

Despite financial aid from Yale, Nooyi worked nights as a receptionist. She went in for interviews wearing a sari because she "had no money to buy clothes."

But she persevered and finished her degree, moving on to the Boston Consulting Group before joining PepsiCo in 1994. Since then, she has been a major part of reshaping the Pepsi brand, overseeing major acquisitions like Quaker Oats and Tropicana, and becoming CEO in 2001. Her salary is now in the tens of millions, dropping from nearly $20 million in 2011 to $12.6 million in 2012, after the company tied compensation to performance.

Yang was born in Taipei, Taiwan, in 1968, and his father died two years later. He moved with the rest of his family to San Jose, Calif., when he was 8 years old. Upon arriving in America, Yang knew just one word of English: "shoe."

But in spite of the language barrier, Yang excelled in school and attended Stanford, graduating in 1990. Five years later, he started Yahoo, which became an Internet powerhouse and helped him accumulate an estimated net worth of $1.15 billion. He stepped down from the company in 2012.

15 Billionaires Who Were Once Dirt Poor >