He fought in the Burma Campaign during World War II, and after the partition of India in 1947, he joined the Pakistan Army and served in the East Bengal Regiment, retiring as a colonel in 1967.

[1][2] Osmani entered politics in independent Bangladesh, serving as a member of parliament and cabinet minister in the government of Sheikh Mujibur Rahman.

[22] Osmani was promoted to lieutenant colonel and became a senior advisor at CENTO headquarters in Baghdad as part of the Pakistan military delegation from December 1955 to May 1956.

After the war, Osmani chaired the committee tasked with determining future army-reserve and logistical requirements and was president of the Army Sports Control Board from July 1965 to April 1966.

The evaluator of the exercises said the Bengali units performed well, their pride in representing East Pakistan a component of their success, and opposed their replacement with mixed regiments.

[39] Toeing the party line, he advised the officers (including M. R. Mazunder, Chittagong martial-law administrator and Rezaul Jalil, CO of the 1st EBR) against "rash" actions.

Bengali ex-servicemen held rallies supporting independence; officers and troops kept abreast of the political situation in East Pakistan, which was becoming uncertain and confrontational.

Majid and Osmani reportedly designed a military plan of action:[40] capture the Dhaka airport and Chittagong seaport, sealing off the province.

Bengali officers advised sabotaging the fuel dumps at Narayanganj and Chittagong to ground Pakistani air power and cripple armed-force mobility.

[41] Bengali soldiers were largely unaware of the larger situation; many units performed routine duties as late as 31 March, rebelling only under Pakistani attack.

Osmani was at the home of Sheikh Mujibur Rahman when Bengali officers informed Awami League leaders of Yahya Khan's departure and the army movements.

Although India did not offer material aid, it helped design Mukhti Bahini structure and expressed the possibility of future Indian intervention.

They began experiencing a lack of trained men, officers, coordination, a central command structure and supplies (despite some aid from the BSF) although most of the country was still free of Pakistani control.

[59] The Bengali political leadership hoped to keep the Pakistanis confined to the cities, while the government in exile sought diplomatic recognition and the resistance prepared for guerrilla warfare[60] and awaited expected Indian military intervention.

[64] From April to June Osmani toured to boost morale and gather information, meeting with his Indian counterparts and setting up the Bangladeshi command structure.

The Indian Army launched Operation Jackpot; by mid-June Bengali soldiers were driven into India, developing the infrastructure for a sustained, coordinated guerrilla campaign.

Although Osmani made strategy decisions and liaised with Indian officers from July to December 1971, he did not organize an operation like the Tet Offensive or lead a battle similar to Dien Bien Phu as commander-in-chief.

His strategy (a product of his military career and the demands of the situation on the ground) influenced his leadership style, and he relied on his background in the Southeast Asian sector during World War II.

His priority was to raise a conventional force of regular battalions and use them to free an area around Sylhet, organizing countrywide guerrilla activity as a secondary effort.

With the conflict largely centred around the India-East Pakistan border region, the Pakistani Eastern Command began reorganizing their forces to consolidate control of the province.

[80] An East Pakistan Civil Armed Force,[81] with 17 operational wings,[82] was raised from West Pakistani and Bihari volunteers, Razakars (50,000), Al-Badr and Al Shams (5,000 from each unit).

[87][88] Denied permission to launch preemptive cross-border strikes, artillery ambushes were laid for Mukti Bahini infiltrators and demining operations conducted.

[96] Osmani lived a Spartan life, wore simple clothes, ate soldiers' food and used camp furniture in Kolkata during the war, acting as an example for his men.

Bengali fighters raised bands to fight the Pakistanis in several areas of Bangladesh (e.g.the Kaderia Bahini, led by Tiger Siddiqi of Tangail is the best-known),[citation needed] and they operated independently.

The Mujib Bahini leadership, initially allowed by Osmani to recruit students and other youths, had an organized, well-armed, trained force with a primary allegiance to Sheikh Mujibur Rahman and their commanders rather than the Bangladesh government.

[107] The government in exile unsuccessfully attempted to bring the Mujib Bahini under Osmani by diplomatic means, approaching R&AW director Ramnath Kao.

[110] According to Indian officer Major General KV Krishna Rao, Osmani's helicopter was shot at by the Pakistan army, and it was not flight-ready to transport him to Dhaka.

[8] Osmani and the Mukti Bahini senior sector commanders met in Dhaka from 2 to 11 January 1972 to discuss the future of the Bangladesh armed forces and other issues.

[130][131] He accepted a post as defense advisor (the equivalent of a cabinet minister) to Khondaker Mostaq Ahmad, who took over as president after the 15 August coup and may have been involved.

[141][142] When Khaled Musharraf learned of the killing of four political leaders in Dhaka Central Jail, he and some staff went to Bangabhaban to negotiate a peaceful transfer of power.