Edward Gilligan, the president of American Express and heir apparent to the company’s chief executive, Kenneth Chenault, died on Friday after falling ill during a flight to New York. Mr. Gilligan, who lived on the Upper West Side of Manhattan, was born on July 13, 1959, in Brooklyn and attended Xaverian, a Roman Catholic high school there, before enrolling at N.Y.U. Mr. Gilligan was appointed president of American Express, the world’s largest issuer of credit cards. He started at American Express 35 years ago as an intern while earning an undergraduate degree in economics and management from New York University. He rose steadily through the company’s ranks, becoming vice president for business travel and later senior vice president for commercial card and business travel for the Eastern United States. In 2002 he moved to London, where he headed the company’s international consumer card division. He returned to the United States in 2009 and led efforts to integrate American Express into social media, helping to embed the company’s offerings on Facebook as well as through tech companies like Uber. He is survived by his wife, Lisa; their four children, Katie, Meaghan, Kevin and Shane; and a brother, Michael.