Mr O'Neill is an economist by training who joined the firm in 1995 as a partner, said the memo, which was signed by Goldman Sachs chief executive Lloyd Blankfein.
He is perhaps best known for coming up with the BRIC acronym in 2001, which identified Brazil, Russia, India and China as top emerging markets where investors could put their money for high returns. He proclaimed that those emerging economies, China's in particular, would help drive markets and world economic growth for the next decade.
Mr O'Neill, once described as the world's first rock star economist for his talent on predicting movements in the $1 trillion-a-day foreign exchange markets, continues to be bullish on China.
Mr O'Neill's calls have been broadly accurate, except for his belief that the world economy was not in trouble during the financial crisis.
In the memo, Mr Blankfein said: "He is an influential economist and thought leader, and is regarded as an expert in the world's foreign exchange and bond markets."
Copyirght @ Thomson Reuters 2013