In 1978 Cohen started his career at Republic National Bank of New York under Edmond Safra. In 1985 he became head of private banking for Banque Safra-Luxembourg and in 1991 head of Republic National Bank of New York. When the bank was acquired by HSBC in 1999 and renamed to HSBC Private Bank Monaco he became its managing director.  In 2016 he resigned.
From 2002 to 2014 he was a member of the international director council of the Guggenheim Museum, New York City, and from 2003 to 2014 of the Tate Modern, London. He currently is the director of the Helmut Newton Foundation, Berlin, the Grimaldi Forum, Monaco, as well as director of Princess Grace Foundation, New York.
International School of Monaco
- "Gerard Cohen". Monaco Wealth. Retrieved 8 June 2017.
- "Gérard Cohen – Former Managing Director at HSBC Private Bank (Monaco) SA". Relationship Science. Retrieved 8 June 2017.
- "ISM Anniversary Gala". The International School of Monaco. Retrieved 8 June 2017.
- "Sovereign Ordonnance n° 1954 of 17 November 2008". Journal de Monaco. Retrieved 8 June 2017.
- "Sovereign Ordonnance n° 8096 of 23 November 2012". Journal de Monaco. Retrieved 8 June 2017.