Husain joined the Pakistan Foreign Service as a member of the first regular batch in 1949. He served in different positions in the Pakistan diplomatic missions in India, The Netherlands, United Kingdom and Thailand. He was acting high commissioner of Pakistan in New Delhi from 1961 to 1964. In 1968, he was appointed as director general in the Pakistan Ministry of Foreign Affairs with Ambassadorial rank. He was appointed as ambassador to Algeria in 1971 but due to Independence movement of Bangladesh, he was detained in Karachi, Pakistan. He accompanied Zulfikar Ali Bhutto on a state delegation to Peking (present Beijing) in November 1971.