What does it mean to be a success? In the days of railroad barons and oil tycoons, it might have meant amassing the most cash possible. These days, the idea of true success has shifted toward the "social entrepreneur" — those who can create thriving enterprises while bringing about positive social change. Here's how a few of the world's top social entrepreneurs about how they got their start.
Related: Best money tips for millennials
Founder, charity: water, which brings safe drinking water to the developing world
First job: McDonald's
"I was around 15 in Flemington, New Jersey, and applied for the job cold. I ended up taking orders and working the takeout window for absolute minimum wage. They did sweeten the pot with free food, though, which for me usually meant Quarter Pounders with cheese. Once I volunteered to dress up as the Hamburglar to hand out coupons because you got paid time-and-a-half. It was a pretty ridiculous costume, with a hat so big that it was difficult to get through doors. I had to tilt my head to one side. I was so terrified of getting recognized by my friends."
Co-founder: Kiva, a microfinance site, and author of "Clay Water Brick"
First job: Art teacher
"I always had a real passion for art. Where I grew up, in a suburb north of Pittsburgh, there was a little family-run art studio. So after 10th grade, I started teaching skills like drawing and painting to kids as young as three. What I took away from that job was the ability to teach: To be able to meet somebody where they are and walk them through something totally new. I am also pretty good at getting people inspired about something. I like to face a problem together and help them figure out where they want to go."
Founder: TOMS, a retailer that provides shoes and other services to those in need, and author of "Start Something That Matters"
First job: Doing laundry
"I was going to Southern Methodist University in Dallas and injured my Achilles tendon playing tennis. I couldn't carry my laundry to the basement, so I looked in the Yellow Pages for a company that could do it for me and nothing like that existed. So I decided along with my college roommate to start a laundry service. We bought an old FedEx truck for $1,500. We were pretty successful, eventually expanding to six universities with 50 employees, and sold it after a few years. But I absolutely refuse to do laundry now. I did more laundry than you can ever imagine. At the time it really sucked, but like anything in life, you look back on it with nostalgia."