JPMorgan announced on Thursday that vice chairman James B. Lee Jr. had died at the age of 62. Colleagues and friends say Jimmy Lee could have been the archetype for a modern investment banker. He was known for developing the art of deal making, networking with corporate higher ups and relentlessly promoting his successes.

According to sources with knowledge of details, Lee became short of breath while running on a treadmill at home on Wednesday morning, and apparently suffered a fatal cardiac event. He died at the hospital.

“Jimmy was a master of his craft, but he was so much more—he was an incomparable force of nature,” JPMorgan CEO Jamie Dimon commented in a statement.

Senior JPMorgan Banker Jimmy Lee Dies At Age 62

More on Jimmy Lee

Jimmy Lee earned a bachelor’s degree from Williams College with a double major in economics and art history. He continued to support Williams and Williams graduates throughout his career.

Lee joined the financial industry in 1975 when he took a job at Chemical Bank. He was one of the first bankers with the idea of breaking up large corporate loans into smaller pieces for several banks, which historians say played a major role leveraged buyout boom of the 1980s.

Lee was a successful executive at Chemical Bank and its successor banks, moving up the corporate ladder until 2000, when he ended up as head of investment banking at Chase Manhattan.

Lee decided to refocus his career on winning deals of all kinds, that is, advising firms on acquisitions and selling themselves, and on raising funds. He played a key role in the merger of United Airlines and Continental Airlines to create United Continental Holdings, he was also involved in the takeover of Wall Street Journal publisher Dow Jones by News Corp, as well as the mega hot IPOs of social media titan Facebook and e-commerce company Alibaba Group.

Of note, before his untimely passing, Lee was involved in one of the biggest deals ever: GE’s plan to sell most of its $500 billion finance division.

Lee was also well known to the media, and made made frequent appearances on television and in the financial press. By the same token, Lee wasn’t shy about himself or his successes, and received some criticism for his selfish attitude.

 Jimmy Lee – Statement from former CEO of GM

On the other hand, clients always got their money’s worth given his relentlessness and his willingness to duke it out for better prices. On the initial public offering for General Motors in 2010, he pushed to make sure the shares sold at a higher price than originally planned, noted Dan Akerson, vice chairman of private equity firm Carlyle Group and an ex-CEO of GM.

“He was street smart, savvy, never overplayed his hand, but he’d push it,” Akerson said.

 Jimmy Lee – Statement from Facebook’s Sheryl Sandberg

Sheryl Sandberg, the COO of Facebook, said Lee “believed in us long before many others did—when we were a small company with little revenue, he told us and anyone else who would listen how much potential he thought Facebook had. He was a trusted counselor.”

Readers can see Dan Loeb’s statement on  Jimmy Lee here.