J.P. Morgan Chase & Co. announced that William Harrison Jr. revealed his intention to retire as chairman and a director of the firm, effective December 31.

It is expected the board of directors will elect CEO Jamie Dimon, 50, to the additional role of chairman when Harrison, 63, retires.

“I have worked my entire career — nearly 40 years – at J.P. Morgan Chase and its predecessor firms, and I am very proud of the leading role we have played in the transformation of global banking and the creation of our world-class franchise,” Harrison said. “I could not be more excited about the future of our firm and the leadership that Jamie Dimon is providing.”

Dimon added, “Bill Harrison has been a tremendous partner and mentor to me. He is a first-class individual — decent and generous. Bill’s strategic vision and his ability to manage complex change have been instrumental in positioning our firm as a leader in global finance. I will miss Bill but hope to continue to benefit from his wise counsel.”