[7] From 1996 to 2007, he served in the Middle East and Central Asia Department of the International Monetary Fund.
[7] From 1994 to 2007, he served as Senior Resident Representative of the International Monetary Fund in Afghanistan, Pakistan, Jordan, Kuwait, Oman, Sudan, and Yemen.
[7][8] Mansur was appointed chairman of BRAC Bank on 27 August 2019 replacing Sir Fazle Hasan Abed after he retired.
[10] Mansur had questioned the GDP figures of the government of Bangladesh which did not match with macroeconomic indicators in 2019 while predicting a slowdown of the economy.
[16] In 2023, he said the economic shock of Bangladesh was also the result of government inaction and not entirely based on external factors.