Key to Success is Believing in Yourself: BlackRock CEO Fink

Believing in yourself is the most important life lesson, Larry Fink, BlackRock chairman and CEO, told CNBC Wednesday. But sometimes, it takes others to have that confidence in you first.

“One needs to have a strong conviction and believe in that strong conviction,” said Fink, who admitted that he lacked that sense during a time of professional turmoil, when he was deciding whether to leave his first job at First Boston and striking out on his own in a business that handled risk management.

In fact, it was Steven Schwarzman and Pete Peterson, co-founders of private-equity firm the Blackstone Group , who put their faith in Fink and his idea, much more than he did in himself, said Fink.

“Both Pete and Steve loved the idea. Within three days, we came to terms with a partnership,” he said Fink. ”Steve and Pete were really gracious: They were very enthusiastic about the idea.”

Watch the next segments of the "My Worst Trades," featuring Blackstone's Steven Schwarzman, Thursday, October 21 on Squawk Box from 6-9 am ET and Power Lunch from 1-2 pm ET.