When Bob Williamson left home at 17, he lived on the streets and did time for heroin possession. But he pulled himself together, got a job, and eventually began his own business as a manufacturer of art supplies. In 1993, Williamson started a company to develop software for cafeterias. Today Horizon Software International supplies more than 15,000 schools, colleges, and universities and has sales of $26 million. Meal payments are made online, and parents can monitor what their kids eat at school. Horizon, based in Atlanta, also sells to hospitals, retirement communities, big corporations, and, soon, U.S. military bases around the globe—"wherever," he says, "large numbers of people need to be fed."

My childhood was tough. My father was in the Air Force. We moved around a lot. When I graduated from high school, I got all hung up in drugs and all that nonsense. I slept on the side of the road; I stayed in missions; I didn't have anything to eat. I fought a lot. I was in jail lots and lots of times.

I had been told all my life that I was worthless and would never amount to anything. I hitchhiked from New Orleans to Atlanta. I had only one change of clothes, and I didn't know anybody. My first job was cleaning mortar off of bricks with a hatchet for $15 a day. Not long after that, I had a head-on collision and very nearly was killed. While I was in the hospital I read the Bible and became a Christian. After that I met my wife. We've been married 37 years.

I went to work for a paint company called Glidden. I had the worst job in the company: I was in charge of the label room, a caged-in area in the basement. But I was promoted eight times in two years to the point where I was managing special projects. I knew a lot of the chemists and taught myself about the chemistry of paint. In my spare time, I was a wildlife artist. There wasn't a good airbrush paint on the market. Everybody was using automotive lacquers. I spent about two years developing one for myself. I'd go to an art show and take my entire inventory. People lined up out of the door. Within about six months, I had distributors and customers all over the country.

I started Wildlife Artist Supply in 1977. I went from my basement to my garage to a little building. Then I went to a 50,000-square-foot warehouse. And I didn't just sell paint. We had a thick catalog, 6,000 or 7,000 items for artists, primarily mail order. It was everything you could imagine: brushes, compressors, clay. I started a magazine to teach people how to do wildlife art. We also founded the World Taxidermy Championships.

In 1988, I made a deal to take the company public. We were going to develop my business into a company like L.L. Bean. My customers were hard-core sportsmen. We were selling wildlife art supplies, so we could have just as easily sold them hunting and fishing stuff.

The next day, my controller turned in his notice. And then a whole bunch of other people quit. I discovered that all of our financial records had been destroyed, and we were $1 million in debt and $278,000 overdrawn at the bank, and my inventory was decimated. It was like a nightmare. I spent two years trying to make him pay. To this day, there's never been anybody but a Williamson reconciling our bank accounts.

There are only so many artists in the world. I wanted to get into something that didn't have any limits. My sons were very gifted in computer technology, and they wanted to start a software company. I had a couple of programmers who worked for me. We had written all this software. The best was our warehouse and distribution package. I had been using it for years in my own stuff. We decided to try selling it. I thought it would be like the paint: I'd just go out there and introduce myself, distributors would pick it up, and I'd be home free. Well, I had a rude awakening. When those big boys are in there, they just stomp you. I realized I had to have a niche.

A rep who worked for me also sold systems to school lunchrooms. I went with him on one of his calls and found out that in the schools there wasn't a system like ours, and there was a tremendous need for it. So I modified my warehouse and distribution system so it would work in cafeterias. The market was too small to attract those big guys, but it was big enough for me. There are 14,000 districts, 97,000 schools. It was a really big opportunity. It seemed unlimited. Everybody's got to eat.

I hired salespeople, but they couldn't sell anything. I told my wife, "I might just do it myself." I had always detested sales and salespeople. But I found out that's what I'm really good at. I went in and told food-service directors how they could save money. They were doing everything manually, and I showed them all the things that our software could do. Within two weeks I had my first order. Then I went to another one, and I went to another one, and pretty soon I had all of Georgia. So I became our chief salesperson. You wouldn't believe how I could sell. I could sell firewood in hell.

It wasn't like I was real flush with cash. Pretty much all my career I was undercapitalized. I borrowed on my home equity and loaded up my credit cards. We started with three or four people, in 1993, and each year we would either double or triple in size. Now we have 173 employees and sales of $26 million.

We ended up developing an A-to-Z software system for managing school food services: warehousing and tracking inventory and sales. For a long time I didn't have any competition. I started looking at other markets. We developed software for colleges and universities and then hospitals and senior living communities. Whoever feeds a lot of people, that's who we go to. We have more than 15,000 installations.

In 2005, we got a $10 million deal with the U.S. military. I worked five years on that deal. Our technology will be in every dining facility worldwide for the Army, Navy, Air Force, and Marine Corps. Every land base, ship, submarine, and remote battlefield.

It's my goal to get junk food out of the schools. Oranges instead of Snickers bars. We've developed technology so kids can buy healthful items from vending machines on their prepaid accounts. And we have software so parents can go online and view what their kids ate that day. I want to help kids make the right nutritional choices. We've got all this technology and all these schools, and we ought to be able to have an impact.