He worked as a marketer for five years at Phibro-Salomon in their offices in New York, Ivory Coast and London. He later moved to Glencore as a marketer in 1992 where he rose through the ranks gaining experience and expertise in coal assets .He was also responsible for regions like Russia, Colombia and Europe .In 2002 Peterson was appointed by Glencore International plc to be the Director of Coal Commodity Department in the firm succeeding Ivan Glasenberg. His responsibilities include overseeing the marketing business globally, managing the assets of the department, strategy and operations. He currently owns 3% of Glencore making him the only American in the Swiss trading powerhouse.