Daniel H. (Don) Callahan is the founder and chief executive officer of Callahan Advisors, LLC, consultants helping global organizations achieve digital transformation.
Acknowledged internationally as a leader in both the financial services and technology industries, Mr. Callahan was most recently the chief administrative officer and global head of operations and technology at Citigroup. Previously he held senior management positions at IBM, Morgan Stanley and Credit Suisse. He retired from Citigroup in December 2018 and now serves on the boards of Tata Consultancy Services, Ltd. as well as WEX, Inc., Accedian and Kore ai.
At Citigroup, Mr. Callahan managed a complex set of businesses and services spanning more than100 countries, a multi-billion dollar operating budget and critical systems infrastructure including the bank’s cyber security initiatives. He most recently led a top-to-bottom transformation of operations and technology, helping move the global bank from a collection of independent and dispersed entities into a lean, fully integrated enterprise. Mr. Callahan also established globally consistent technology standards and governance, and migrated critical functions to an integrated, managed, shared services model.
Earlier in his career, Mr. Callahan spent 12 years at IBM, where he held a number of management positions, including director of strategy for IBM Japan.
He currently serves on the business committee of the Metropolitan Museum of Art, as a fellow at the Foreign Policy Association and on the boards of the American Red Cross New York Region and the New York Hall of Science. He holds a bachelor’s in history from Manhattanville College, we he serves as trustee chair emeritus.