Momen was born on 23 August 1947 in Sylhet. He passed the matriculation exam from Sylhet Government Pilot High School. He attended the University of Dhaka and earned a BA in economics in 1969, and an MA in development economics in 1971.

Momen became a civil servant, serving as Private Secretary to the Minister of Rural Development, Local Government and Cooperatives from 1973 to 1974; Private Secretary to the Minister of Trade and Commerce, and Mineral Resources and Petroleum from 1974 to 1975; Section Officer, South Asia, East Asia and Middle East, Ministry of Commerce from 1975 to 1976; and Director, Office of the President’s Advisor on Trade and Commerce from 1976 to 1978. Meanwhile, he completed an LLB in law and jurisprudence from Central College, Dhaka, in 1976.

Momen continued his education in the United States, receiving a PhD in economics from Northeastern University, Boston, Massachusetts, in 1988. He taught economics and business administration at Merrimack College, Salem State College, Northeastern University, the University of Massachusetts, and the Kennedy School of Government at Harvard University.

In 1998, Momen became an economic adviser at the Saudi Industrial Development Fund (SIDF). He left Saudi Arabia in the wake of the 2003 Riyadh compound bombings, and returned to Massachusetts. There he taught in the Department of Economics and Business Administration at Framingham State College until appointed Bangladesh’s Permanent Representative to the United Nations in New York in August 2009.

Momen served as President of the UNICEF Executive Board at the international level in 2010. He was Vice President and Acting President of the 67th United Nations General Assembly.

Momen was President of the United Nations High-Level Committee on South-South Cooperation in 2014.

Momen’s elder brother, Bangladesh’s Minister of Finance Abul Maal Abdul Muhith, hoped that Momen would succeed him as a member of the parliament representing the Sylhet-1 constituency in the 2018 general election, which he eventually won.