Reuters/ Ueslei Marcelino
Cohn is the President and COO at the firm, and trails only CEO Lloyd Blankfein in stature.
The National Economic Council (NEC) advises the president on US and global economic policy.
Trump appointed former Goldman Sachs banker Steven Mnuchin Treasury secretary last month. And Steve Bannon, his incoming chief strategist, is also a Goldman Sachs alum.
Goldman shares are up by about 30% since Trump's victory on November 8.
The President-elect was highly critical of the Wall Street bank throughout his campaign. He condemned Democratic nominee Hillary Clinton for her ties to Goldman Sachs and other Wall Street firms - and for earning hundreds of thousands of dollars for speeches given to the global investment bank and its clients.