In May 2009, Farmer was named Chair of Harvard Medical School's Department of Global Health and Social Medicine, succeeding Jim Yong Kim, his longtime friend and colleague. In 2012, Kim was appointed President of the World Bank. On December 17, 2010, Harvard University's President, Drew Gilpin Faust, and the President and Fellows of Harvard College, named Farmer as a University Professor, the highest honor that the University can bestow on one of its faculty members.
In August 2009, Farmer was named United Nations Deputy Special Envoy to Haiti (serving under former U.S. President Bill Clinton), in his capacity as Special Envoy.