Do Won Chang, co-founder and CEO of Forever 21

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.