Jimmy Lee's "force of personality" and relentlessness made him an executive who always got deals done, former General Electric chief Jack Welch said Thursday, a day after the unexpected death of the 62-year-old JPMorgan vice chairman.

"It is with deep sorrow and a heavy heart that I inform you that our beloved friend and colleague, Jimmy Lee, unexpectedly passed away this morning," JPMorgan Chairman and CEO Jamie Dimon said in a statement. "Jimmy was a great friend, leader and mentor to me and so many others."



James B. Lee Jr. led the company's investment banking arm, and was known for his work on the syndicated loan market among other things.



He oversaw major mergers and acquisitions deals including the sale of General Electric assets, the General Motors and Alibaba IPOs (the two largest U.S. IPOs ever), the United-Continental merger and the Comcast-NBCUniversal merger, according to a company spokesman.

Read More On the Record: Jimmy Lee, JPMorgan Chase



"As Vice Chairman of our company and former head of our Investment Bank, Jimmy made an indelible and invaluable contribution to our company, our people, our clients and our industry over his nearly 40 years of dedicated and selfless service. Jimmy was a master of his craft, but he was so much more—he was an incomparable force of nature," Dimon said in his statement.

Lee told CNBC in 2010 he felt lucky for having his job.

"I love coming to work every day. I'm lucky in the sense that I get to work on, and many times run, our biggest transactions. I like the content of what I do and who I do it with," he said at the time.



Lee was exercising at his home in Connecticut when he felt short of breath, CNBC learned.

He is survived by his wife, Beth, and three children—Lexi, Jamie and Izzy—according to Dimon's statement.



"I've got a great wife, I got three great kids. I love being with them. To me the family unit is an important sacred place and I enjoy that the most," he told CNBC in 2010.