Mahbub joined the Foreign Service cadre of the Bangladesh Civil Service in 1985. He had served in the
Permanent Mission of Bangladesh to the United Nations and
Permanent Mission of Bangladesh to the United Nations in Vienna. He had served in the embassy of Bangladesh in Japan. He was the director general South Asia and South Asian Association for Regional Cooperation at the Ministry of Foreign Affairs in 2006. He was the high commissioner of Bangladesh to Sri Lanka in November 2011. Mahbub was appointed the high commissioner of Bangladesh to Singapore in 2012. He replaced
Kamrul Ahsan. During his term the Zika virus spread to the expatriate Bangladeshi community in Singapore in 2016. From 2016 to 2019, Mahbub was the secretary in charge of Asia and Pacific region at the Ministry of Foreign Affairs. On 21 August 2019, Mahbub was appointed the ambassador of Bangladesh to China for one year. In June 2022, Mahbub hosted the director general of the
Department of Asian Affairs who called Bangladesh to reject "cold war mentality" of the United States. ==References==