“He would give me an industry you might know something about, like a restaurant,” Dimon said on a recent episode of The Master Investor Podcast with Wilfred Frost. “And say, ‘Okay, look at this. Look at the history. Read the annual report. Study the industry if you want. What would you pay for the stock?”

That early training would prove foundational. Dimon, now 70, has run JPMorgan Chase for nearly two decades and built it into the largest bank in the U.S.—but the instinct for pricing a business started at his father’s side, long before business school.

A Wall Street stockbroker, Dimon’s father, Theodore, encouraged all three of his sons to learn more about the markets, but only Jamie leaned in. While his brothers showed little interest, Dimon gravitated toward big business bets and used the simulation games to learn the fundamentals of stock picking and decision making. 

“It is brutally hard,” Dimon said. “Then you learn the ‘why.’”

By high school, Dimon’s idea of leisure reading was anything but typical: he spent his spare time reading books, papers, and reports on psychology, economics, and accounting.

“I read Graham and Dodd in high school—I was a nerd,” Dimon said. “I read all of Freud’s books. I always would be taking this stuff in.”

At 14 years old, Dimon bought his first stock in 1970 with guidance from his father, and never looked back.  He went on to graduate from Tufts University before earning an MBA from Harvard Business School. After graduation, Dimon landed his first Wall Street role as an assistant to then-American Express president Sanford “Sandy” Weill. 

“My first goal was to learn something and not say anything until I could add some value,” a 28-year-old Dimon told Fortune in a 1984 profile.

The apprenticeship under Weill became Dimon’s real business school. Dimon had joined Weill as his assistant at American Express in 1982, and when the two left to take over consumer lender Commercial Credit in 1986, Dimon became CFO at just 30 years old. Under Weill’s mentorship, Dimon learned the inner workings of banking, a foundation that paved the way for more senior positions at Citigroup and Bank One, the latter of which merged with JPMorgan Chase in 2004. Two years later, in 2006, Dimon became the CEO of JPMorgan Chase. 

Today, Dimon is one of the only remaining Wall Street CEOs still in place from the 2008 financial crisis. He led JPMorgan for nearly two decades, making him an outlier among his peers, whose tenures typically lasted under a decade, according to Esgauge data. The bank is now the largest bank in the U.S., and ranked No. 12 on the Fortune 500 list and No. 19 on the Global 500. 

In 2025, the bank generated $185.6 billion in revenue, a $5 billion increase from the year prior, according to JPMorgan’s 2025 annual report.

Dimon’s financial prowess has also translated into personal wealth. His net worth stands at $3.2 billion, according to the Bloomberg Billionaire’s Index. 

Dimon’s success

When asked whether he always believed he would lead JPMorgan Chase to a market capitalization approaching $1 trillion, he answered bluntly: “No.”

Instead, Dimon described a philosophy grounded more in discipline than ambition. While his interest in finance was shaped early by his father, he said his strategy is inspired by elite athletes as much as his Wall Street peers. 

“I think you get in trouble if you say, ‘I want to be the biggest bank in the world,’” Dimon said, pointing to NFL legends Tom Brady and Peyton Manning. “They say they didn’t have the best arm and they weren’t good runners, but they became the best.”

It’s a philosophy he’s shared before. At the Fortune Most Powerful Women Summit in 2025, Dimon told Fortune Editor-in-Chief Allyson Shontell he gives 100% effort “every day, every meeting.” And although not every attempt is going to be successful, it’s imperative to remain diligent.

“You can’t hit a home run every time you’re at the bat,” Dimon told Shontell. “You keep working, stay humble, and work hard.”

It’s the same lesson his father set out over annual reports half a century ago: do the work, and understand the why.