In 1954, Khondakar Mostaq Ahmad, a United Front candidate, won a seat in the East Bengal legislative Assembly. Mostaq Ahmad was imprisoned in 1954 following the breakup of the United Front cabinet by the adoption of Article 92-A. After being freed in 1955, he was chosen as the United Front parliamentary party’s chief whip. But when martial law was declared in the nation in 1958, he was once more imprisoned. After introducing the six-point programme in 1966, Mostaq Ahmad was once more imprisoned. Beginning in early 1969, eight national political parties established the anti-Ayub Committee of Ganatantrik Sangram Parisad (Democratic Resistance Front), and Mostaq Ahmad was chosen as the East Pakistan wing’s convenor.

He was a representative of the Awami League in the Round Table Conference in Rawalpindi, Pakistan, in 1969, which was organised by Muhammad Ayub Khan. In 1970, he was chosen to serve in the Pakistan National Assembly.

Mostaq Ahmad served as a minister in the mujibnagar government during the liberation struggle and was in charge of parliamentary, legal, and international affairs. Following his freedom, he joined Bangabandhu sheikh mujibur rahman’s cabinet (1972–1975) and was responsible for power, irrigation, and flood control ministries. He was appointed to lead the ministry of business in 1975. He was on the Bangladesh Krishak Sramik Awami League’s executive committee, which was established in 1975.

Mostaq Ahmad proclaimed himself the President of Bangladesh after a group of army officers killed Sheikh Mujibur Rahman on August 15, 1975. He held this office for 83 days in total. However, he quickly issued the Indemnity Ordinance after seizing the president. He altered the name of Bangladesh Betar to “Radio Bangladesh” and the motto “Jai Bangla” to “Bangladesh Zindabad.” Four national leaders who were detained in the Dhaka Central Jail during his rule—Syed Nazrul Islam, Tajuddin Ahmad, Captain M Mansur Ali, and Ahm Qamaruzzaman—were brutally murdered (3 November 1975). On November 5, 1975, Mostaq Ahmad’s presidency was terminated.

In 1976, Mostaq Ahmad launched the Democratic League, a brand-new political organization. He was detained the same year for his claimed participation in a plot to topple the military regime. He was found guilty in two corruption trials brought by the military administration and received a five-year prison term.