Image source: The Motley Fool.

The best thing about JPMorgan Chase's (JPM 0.24%) stock has little to do with the stock itself, and more to do with the underlying fundamentals of the business. More specifically, if you buy shares of the nation's biggest bank by assets, you'll be aligned with one of the best bankers alive today.

Getting to know Jamie Dimon

JPMorgan Chase chairman and CEO Jamie Dimon didn't follow the conventional path. After graduating near the top of his class at Harvard Business School, Dimon turned down some of the most coveted jobs in the financial industry, including the opportunity to work at Goldman Sachs.

He instead chose to go and work under Sandy Weill, the president of American Express at the time and a well-known financial services empire builder. Weill was soon ousted from his post at the credit card giant and, along with Dimon, took control of a consumer credit company. They then expanded it over the years until, eventually, after merging with Citicorp in 1998, the company became what's known today as Citigroup.

JPMorgan Chase chairman and CEO Jamie Dimon. Image source: JPMorgan Chase.

Dimon became president at Citigroup, but was himself ousted by Weill not long after the merger, which created the first true universal bank in the United States since the Glass-Steagall Act was passed in the midst of the Great Depression. Dimon wasn't fired because he did anything wrong, but rather because he refused to promote Weill's daughter to a position Dimon didn't believe she was qualified for.

After a brief hiatus, Dimon was hired to run Bank One, a regional bank based in Chicago at the time that ranked fifth in the country in terms of assets. He turned Bank One around, boosting not only its efficiency but also morale. He did the latter in part by investing a substantial part of his net worth in the bank's stock upon taking the helm.

Dimon joins JPMorgan Chase

Fast-forward to 2004, when JPMorgan Chase approached Bank One about a potential merger. The deal was attractive to JPMorgan Chase not only because it would give the Wall Street bank access to Bank One's plentiful retail deposit base, but also because it secured Dimon as the successor to William Harrison atop the combined firms.

This was a prudent move. Dimon proceeded to improve the operations at JPMorgan Chase, much like he did at Bank One. And he was the single most important reason that the New York City-based bank not only survived the financial crisis of 2008, but actually thrived because of it.

At the darkest points of the crisis, the government came to JPMorgan Chase twice for assistance (most other banks went in the opposite direction, hat in hand to the government). In March 2008, JPMorgan Chase rescued Bear Stearns, the fifth-largest stand-alone investment bank at the time. And six months later, JPMorgan Chase came to the rescue again, taking over the failed savings and loan giant Washington Mutual.

These moves, combined with impressive organic growth under Dimon's watch, enabled JPMorgan Chase to climb once again to the apex of American finance, after years of lingering behind Citigroup and Bank of America. To this end, JPMorgan Chase is now the biggest bank in America by assets. And if you include assets under custody, it oversees around $30 trillion worth of on- and off-balance-sheet assets.

And I'm not the only one who thinks highly of Dimon. Warren Buffett, one of the greatest bank investors in American history, praises the bank CEO regularly. Most recently, Buffett described an interview that Dimon sat for as "off the charts." And while Buffett's company, Berkshire Hathaway, doesn't own shares of JPMorgan Chase, Buffett himself does. It was recently announced as well that one of Buffett's lieutenants at Berkshire has agreed to join JPMorgan Chase's board of directors.

If you're considering buying shares of JPMorgan Chase and are wondering about the best reason to do so, I'd say it's none other than Jamie Dimon.