[2][3] From 1996 to 2000, Leaf served as the Department's Middle East "Watcher" at the U.S. Embassy in Paris, reporting on French policies on Iraq, Iran, the Arab-Israeli dispute, Libya, and terrorism issues.

From 2003 to 2004, she directed the Regional Headquarters of the Office of the High Representative (OHR), in Tuzla, Bosnia-Herzegovina, enforcing implementation of civilian aspects of the Dayton peace accords, including the return of refugees to areas from which they had been ethnically cleansed.

Provincial Reconstruction Team in the strategic province of Basrah, Iraq, from 2010 to 2011, leaving an assignment as Political Minister Counselor at the U.S. Embassy in Rome, Italy, to oversee the PRT's transition to a U.S. Consulate General.

[4] Leaf was the Ruth and Sid Lapidus Fellow at The Washington Institute and director of the Geduld Program on Arab Politics from 2018 to 2022.

[2] In January 2021, Leaf was named the National Security Council Senior Director for the Middle East and North Africa for the Biden administration.