In 1937, Habibullah Khan joined the Khaksar movement and worked in the North West Frontier Province.

He was one of the leading lawyers in the region mostly practicing criminal cases in the then District Headquarters in Bannu.

He lived in Bannu for his legal practice and returned to family home in Lakki Marwat occasionally.

Upon the partition of India in 1947, Habibullah Khan opted for a career in law and became the first District and Sessions Judge of Peshawar High Court in 1947.

He remained acting President of Pakistan from 1977 until 1978, when martial law was imposed on the country by General Muhammad Zia-ul-Haq.