This is the key lesson Warren Buffett learned from buying his first stock at age 11

Warren Buffett bought his first stock at 11

Warren Buffett got into the investing game early. He bought his first stock — shares of Cities Service for $38 apiece — at age 11. Since, the investing legend has amassed a fortune of $75 billion and become one of the richest men in the world.

What he's learned since buying his first stock in 1942 is to buy, hold and not watch the markets too closely.

"No matter what the headlines say … American business is going to do fine over time," Buffett tells Judy Woodruff of PBS NewsHour. "Occasionally we go off the tracks with bubbles … but it will never permanently derail us."

In fact, when he bought his first stock in 1942, the headlines didn't look good, he notes: "We were losing the war in the Pacific."

Warren Buffett's secret to investing lays in the game of baseball

Markets go up and down every day, but that doesn't necessarily mean there's significance to every move. As an investor, it helps to be patient, and to accept a certain level of uncertainty.

Since buying his first stock at age 11, "75 years have gone by and I've never known what the market is going to do the next day," Buffett says. "That's not my game. My game is to decide whether I'm in the right economy, which America has definitely been ever since that time."

Rather than trying to time your investments, buy and hold for the long term, Buffett tells CNBC: "The money is made in investments by investing, and by owning good companies for long periods of time. If they buy good companies, buy them over time, they're going to do fine 10, 20, 30 years from now."

It's what he's been doing since the 1940s and what he still does today, regardless of the headlines.

"I've owned stocks consistently since 1942," Buffett tells PBS. "I was buying stocks the day before the [2016] election. I was buying stocks the same day after the election. Had Hillary been elected, it would've been the same thing."

Like this story? Like CNBC Make It on Facebook.

Don't miss: Here's how Warren Buffett hustled to make $53,000 as a teenager

Warren Buffett keeps his breakfast under $3.17