in Mathematics and Political Science from Stanford University and a Master of Public Policy from the John F. Kennedy School of Government at Harvard.

[1] The title of his Harvard public policy thesis was Unintended Consequences: Critical Assumptions in the Clinton Health Plan.

Prior to joining the White House staff, Hennessey worked for Senate Majority Leader Trent Lott from February 1997 to August 2002.

While in Senator Lott's office, he was involved in the Balanced Budget Act of 1997 and all budget resolutions since 1997, the Economic Growth and Tax Relief Reconciliation Act of 2001 and all tax legislation since 1998, Trade Promotion Authority, all health legislation, the Transportation Equity Act, FAA authorization bills and many other smaller bills.

Hennessey was a research assistant for the Bipartisan Commission on Entitlement and Tax Reform from June 1994 to January 1995.