Habibullah Khan was the first Chairman of the Senate of Pakistan from 6 August 1973 until 5 August 1975, and was consecutively elected chairman for the second term of the Senate from 6 August 1975 until 4 July 1977. He remained acting President of Pakistan from 1977 until 1978, when martial law was imposed on the country by General Muhammad Zia-ul-Haq.
Habibullah Khan served as the first Chairman of the Senate of Pakistan from August 6, 1973, to August 5, 1975, and was re-elected for a second term in that position from August 6, 1975, until July 4, 1977. He held the acting presidency of Pakistan from 1977 until 1978 when General Muhammad Zia-ul-Haq imposed martial law on the country.