Mujib left Muslim League to join Suhrawardy and Maulana Bhashani to form the Awami Muslim League, the predecessor of Awami League. He was elected MLA in 1953 and served briefly as Agriculture Minister in A. K. Fazlul Haq's government.
Mujib was elected to the second Constituent Assembly of Pakistan and served from 1955 to 1958. In 1956, East Bengal was renamed East Pakistan, and it was opposed by the Awami League.