He was most recently the United States Special Representative for Afghanistan and Pakistan and is currently a Vice Chairman of The Cohen Group, a business strategic advisory firm headed by former U.S. Secretary of Defense William Cohen, and a Vice Chair of the German Marshall Fund board of trustees.

[7] He served as the Deputy Director of the Private Law Office of Peter Carington, 6th Baron Carrington, Secretary General of NATO, from 1983 to 1986.

[citation needed] Grossman served as Deputy Chief of Mission at the United States Embassy in Ankara, Turkey from 1989 to 1992.

Grossman was appointed Under Secretary of State for Political Affairs, the Department's third-ranking official, in March 2001.

[10] In January 2005, Grossman resigned from his position and joined The Cohen Group, an advisory firm providing corporate leadership with strategic advice in government regulation and raising capital.

[11] The Cohen Group has close connections to the Turkish Army and represents some of the US’s largest weapons manufacturers, which stand to benefit from weapons sales to Turkey: Lockheed Martin, General Dynamics and Sikorsky Aircraft among others, and their list of clients includes controversial firms such as DynCorp International, a major national security contractor with the US government, charging billions for overseas military and police training.

[12][13] In late 2005, Grossman also joined Ihlas Holding, a Gülen-linked Turkish conglomerate which is also active in several Central Asian countries.