There are two schools of thought when it comes to the right time to become a philanthropist.
Some like Steve Jobs believe you should spend most of your life making your fortune and giving it away only toward the end. Others, like Mark Zuckerberg, have started on the road to philanthropy at the same time they started the road to great wealth.
Citigroup founder and philanthropist Sandy Weill said that young entrepreneurs and executives should start giving to charity as early as possible. He added, executives who say they have no time are just looking for an excuse.
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During an interview Wednesday on CNBC's "Squawk Box," Weill said, "The biggest merger was 1998 when Citi merged with Travelers. And I became the chairman of that, running a company in 100 different countries with 250,000 people, and I made the time."
Weill also added that when aspiring business leaders become philanthropists early in their career, it helps them to ultimately become better business leaders and people.
"People should start young," he said. "I think philanthropy is really about brains. When somebody comes out of college, they get a job at Twitter or Clorox, that person also gets involved in things in the community. I guarantee you that person will end up doing better in the company he is working for. He'll feel better about it. And he'll get other people to follow him. So I think this is something that we should teach, and people who give graduation speeches, should talk about."
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Weill, in his life, has given hundreds of millions of dollars to different philanthropic causes including Carnegie Hall, Weill Cornell Medical College and most recently the Green Music Center at Sonoma State University.
—By CNBC's Robert Frank.
(CORRECTION: An earlier version of this story misstated the name of the medical college that was supported by Sandy Weill.)