Following his graduation, Manzur joined the
Pakistani Army, subsequently attending the
Pakistan Military Academy and the Defence Services Staff College in Canada, where he obtained his
PSC in 1968 From there, they made their way to Bangladesh, and Manzur joined up with fellow officers from East Bengal. He quickly became a prominent officer within the ranks and won many battles in his sector. He commanded Sector – VIII during the Liberation War from September 1971 to victory in December 1971. In 1974–76, he was posted in New Delhi as
military attaché in the High Commission of Bangladesh to India. Known for his tenacity, keen eye for strategy, and formation of loyalty from colleagues, in 1975 he was promoted to
colonel. Upon his return to Dhaka in March 1977, he was promoted to brigadier general. After the
1977 Bangladesh Airforce Mutiny, Manzur succeeded his colleague and rival major general
Mir Shawkat Ali as the
Chief of the General Staff on October 1977. He suggested that the air force should have a limited potentiality or be restructured as a directorate under the newly
Bangladesh Army Aviation Group. In March 1980, he was promoted to
major general at the age of 41 making him as one of the youngest
flag officer in South Asia's history. On December 1980, Manzur was appointed as the
GOC of
24th Infantry Division and area commander,
Chittagong area. lieutenant general
Hussain Muhammad Ershad, then chief of army staff soon gave transfer order to Manzur to a non-combatant post in Dhaka as commandant of the
Defence Services Command and Staff College around March 1981. This put him in direct opposition to president
Ziaur Rahman as he wanted to stay in an operational assignment. He appealed his posting order to army headquarters, but was denied as Rahman wanted to separate him and
Mir Shawkat Ali at same regional installations. == Role in assassination of Ziaur Rahman ==