The hire of Peter Orszag, currently a senior fellow at the Council on Foreign Relations, is the second by Citi of a former senior government official in less than a week.
Orszag had worked as director of the Office of Management and Budget under President Barack Obama, and left last July.
Orszag will also be a member of Citi's senior strategic advisory group, but Citi said in a prepared statement his role will not involve direct contact with federal government officials.
Prior to working as the Office of Management and Budget director under Obama, Orszag oversaw the Congressional Budget Office. He holds a doctoral degree in economics from the London School of Economics.
The hire comes just six days after the bank hired Carlos Gutierrez, former Commerce Secretary under President George W. Bush, as a vice chairman for its institutional clients group. Gutierrez worked as commerce secretary from 2005-2009.
(Reporting by Joe Rauch, editing by Gerald E. McCormick)