Ansari submitted his M. A. thesis in 1959 and enrolled for a Ph. D. under the supervision of a well-known Muslim scholar of Pakistani origin, Professor Fazlur Rahman (1919-1988). He wrote his dissertation on “the early development of Fiqh in Kufah, with special reference to Abu Yusuf and Al-Shaybani.” Professor Fazlur Rahman left the Institute in 1961, but Ansari carried on with his research and submitted his dissertation in 1966. While at Montreal, Ansari travelled to Cairo and enrolled at an Islamic academy “M’had al-dirasat al-Islamiyyah”, where he came in contact with Muhammad Abu Zahra (1899-1974), a distinguished Egyptian scholar, and other Egyptian ulama.
Following the completion of his doctoral work, Ansari embarked on a teaching career, which took him to several countries. He began his teaching career the Department of Oriental Studies at Princeton University, New Jersey, USA, in 1966. The following year he travelled to Saudi Arabia to take up a teaching position at King Abdul Aziz University, Jeddah. He spent 16 years, from 1970 to 1986, at the University of Petroleum and Minerals at Dahran, Saudi Arabia. He did brief teaching stints at the University of Melbourne, Australia (1976), McGill University (1976-77) and the University of Chicago (1979).
In 1986 Dr Ansari began his life-long association with the International Islamic University, Islamabad, Pakistan, where he was appointed, at different points of time, Professor and Dean of the Faculty of Shariah and Law, Director General of Shariah Academy, Director General of Islamic Research Institute and Professor Emeritus. He also served as President of International Islamic University.
Since his student days, Dr Ansari was profoundly inspired and influenced by the ideas and writings of Mawlana Sayyid Abul ‘Ala Mawdudi (1903-1979), a well-known Islamic scholar of the Indian subcontinent. In 1979 he co-edited, with Professor Khurshid Ahmad, a festschrift in honour of Mawlana Mawdudi, Islamic Perspectives: Studies in Honour of Sayyid Abul ‘Ala Mawdudi.
Dr Ansari’s most ambitious work is the English translation of Mawlana Mawdudi’s commentary on the Quran, Tafhim al-Quran. The translation, named Towards Understanding the Quran, was published in 10 volumes by the Leicester-based Islamic Foundation over a period of 12 years (1988-2010).
An abridged edition of the English translation was brought out in 2006. Dr Ansari had a deep and abiding interest in inter-faith and inter-cultural dialogue. In 2001 he co-edited, with John L. Esposito, Muslims and the West: Encounter and Dialogue. The volume sought to trace the roots of Islamophobia in the West and, at the same time, emphasized the need for inter-civilizational dialogue. Dr Ansari also edited a prestigious quarterly journal Islamic Studies.