FORTUNE — Duncan Campbell, 69, remembers lying in bed late at night as a child and hearing his parents stumble home from the bars. His mother was an alcoholic, and his father was in and out of prison. Growing up in low-income housing in Portland Ore., Campbell didn’t have anyone to attend his Boy Scout ceremonies, much less encourage him to succeed.

A vast majority of children replicate the behavior of their parents. It would have been easy for Campbell to follow that trend. Yet for reasons he has a hard time explaining, Campbell not only graduated from high school, but also got his undergraduate and law school degrees from the University of Oregon. He paid for his education by living at home and taking on three jobs: a night job washing dishes, a weekend job pumping gas, and a summer job washing cars.

“I grew up in a classic welfare family,” says Campbell. “My parents lived in bars and taverns. I was about 9 when I made a conscious decision not to be like my parents when I grew up. That was the catalyst for later success.”

MORE: From tech to tree tops

Campbell went on to become a certified public accountant for Arthur Andersen during the firm’s heyday. He quickly realized CPA work wasn’t for him and searched for ways to start his own business. A majority of his clients were in the forest industry, and as they were suffering from a relatively low return on investment from their crops, Campbell saw an opportunity. Creating one of the first forest and nature resource investment firms in 1983, Campbell monetized timberland by managing it for large institutional investors. His firm, now known as Campbell Global, is responsible for more than 3.1 million acres of land worldwide.

“We built the entire business on cold calls,” says Campbell. “Investment firms invested in stocks, bonds, and maybe real estate, but not timberland.”

After selling the company in 1990, Campbell found himself in a financial position to donate millions to a cause of his choosing. Prior to fully retiring, he volunteered frequently with the juvenile court system in Portland and made an effort to get to know the troubled youth. Campbell would see the same children getting in trouble time and time again, but he knew that a majority of them wouldn’t be there if they just had someone in their life that cared about them.

MORE: From foreclosures to fighting for homes

That’s when he drew upon his own neglected childhood to develop an organization that gave others exactly what he lacked growing up: a friend.

Friends Of The Children, founded by Campbell in 1993, provides mentors for at-risk children. Mentors, or friends, are paid professionals who develop relationships with inner-city kindergarteners or first-graders and maintain contact with the children through high school.

“We do a reverse draft,” explains Campbell. “We go in and ask for the most-challenged kids in the school. We don’t say give us your best kid with the most promise. We say ‘Give us the kid that is giving you the most trouble and you think will drop out, get into the justice system, or be an early parent.’”

It took several years for the program to see real results, but Friends Of The Children is clearly having a positive impact. Roughly 85% of the 1,000 kids that participate in his program nationally graduate from high school, and 94% stay out of the justice system. Aside from its flagship program in Portland, Friends Of The Children now operates in Harlem, N.Y., Boston, Seattle, and another small community in Oregon. Campbell is planning on opening another office in Tampa Bay, Fla. soon.

MORE: From selling to service

“Most people think I had a great mentor growing up, and that’s why I started the program, but it was because I didn’t have one that I knew how important a friend could be,” says Campbell.

The primary goal of the organization is to support participants to earn a high school degree, but it’s evident that mentors inspire many to achieve more. About 50% of the children go on to get further education at either a two-year or four-year graduate program.

In a recent board meeting, Campbell found himself crying. A child from one of his original programs just graduated from college and is now coming back to Friends Of The Children to mentor kids himself.

“I tell people that the last four or five years have been the best years of my life,” says Campbell. “To wake up in the morning and be able to work with children is incredible. I encourage everyone to do something where they can make their communities better.”

WORDS OF WISDOM

What he wishes he knew before the switch

“I was so naïve in the ways of the general world. I wish I had a broader experience early on and that I had met the kind of people that I have been fortunate enough to meet in the last 20 years. I have met people all over the country who have a similar interest and passion, and I wish I had these contacts earlier.”

Biggest challenge

“By far the biggest challenge is raising funds. Our success rate brought us to national attention, and yet breaking through the cycle of traditional fund raising is hard.”

Biggest reward

“Being with the children from time to time and the spirit of all the friends. I got to create the culture of the organization from the start, so when I walk into the meeting or one of our buildings, there is a sense that this is different than any business or non-profit work. That is very fulfilling.”