He became seriously ill on a flight home to New York this morning, the statement said.
"This is deeply painful and frankly unimaginable for all of us who had the great fortune to work with Ed, and benefit from his insights, leadership and enthusiasm," CEO Ken Chenault said in the statement.
"Our thoughts and prayers go out to his wife, Lisa, and their four children - Katie, Meaghan, Kevin and Shane. He was a proud husband and father, and his love for his family was evident in all that he did."
Gilligan became president in April 2013, after serving as vice chairman from 2007. He joined the credit card giant in 1980.
In afternoon trading, shares of afternoon trading were down about 0.5%.
Here's the full statement:
With the heaviest of hearts, I must share some devastating news. Ed Gilligan - President of our company and friend and inspiration to many inside and outside American Express - became seriously ill on a flight home to New York this morning and has passed away.
This is deeply painful and frankly unimaginable for all of us who had the great fortune to work with Ed, and benefit from his insights, leadership and enthusiasm. Our thoughts and prayers go out to his wife, Lisa, and their four children - Katie, Meaghan, Kevin and Shane. He was a proud husband and father, and his love for his family was evident in all that he did.
Ed also loved American Express. He devoted his entire career to this company, starting as an intern 35 years ago and moving steadily up all the way to Vice Chairman in 2007 and President in 2013. His contributions have left an indelible imprint on practically every area of our business, from Commercial Card and Travel to International, Consumer, Small Business, Merchant Services, Network Services and, most recently, the group forging our digital partnerships and driving payment innovations. Ed was a living embodiment of our values, embracing both our heritage of service, trust and integrity, as well as our entrepreneurial spirit that has helped continually transform this company through the years. For the time being, I have asked Ed's direct leaders to report to me.
The mark of a true leader is followership, and Ed won the hearts and minds of many thousands. He was a champion of diversity and employee development, and his mentorship has helped create a legacy of strong leaders wherever he went. We mourn his loss, and we will have opportunities to share our memories of him more fully in the coming days. More details will be communicated next week.
In this moment, I know you will join me in personal remembrances of Ed.