He started his Quranic education at Ali Bahi mosque in Tela, where he was taught by Mohamed Abidi, Ali Bahi mosque's Imam. He went to primary school and secondary school in Tela.
Khadmi received his diploma in jurisprudence and Islamic politics from Zitouna University of Shariaa and theology in 1966.
He received two PhD’s in jurisprudence (with thesises on Thahereya and the Malki school of Islam) from the Higher Institute of Islamic Theology at Zitouna University, in 1993 and 1997.
He taught courses on Islamic sciences and Shariaa texts in several institutions in Tunisia and Saudi Arabia
Kadmi is a Member of the International Committee of the Organization of Islamic Congress’s Bioethics Commision.
He works as a researcher for the Arab Encyclopedia at the Arab Organization for Education, Science and Culture. Khadmi also is a researcher for the Encyclopedia of Fundamentalism in Kuwait.
Khadmi collaborates with the Center for Research and Islamic Studies in Riyadh and with the Research Magazine of Contemporary Jurisprudence. He has also contributed to several radio programs on Holy Quran Radio of Riyadh.
Khadmi has authored several books and publications.