He obtained his PhD degree in 1989 for his dissertation on The Qadiri Sufi Order, with a study and edition of the poetical works of Abdul Qadir al-Jilani.

He has placed consistent emphasis on the study of Ibn Arabi and Abdul Karim al-Jili, regarded as two of the most important figures of philosophical Sufism in the history of Islam.

Ziedan's work as a public intellectual is reflected in several of his later works, including Arabic Theology and Rationals Behind Religious Violence اللاهوت العربي وأصول العنف الديني which examines the dynamics behind the key ideas that shaped the faiths of Judaism, Christianity, and Islam, and their links to each other and to the geography of the region.

His scholarly career has included extensive explorations of the scientific heritage of Arab peoples throughout history, with special focus on medicine.

Ziedan's second novel is the historico-theological work Azazeel (عزازيل), which won the 2009 International Prize for Arabic Fiction.

An Egyptian monk called “Hypa” wrote the original manuscript as an autobiography in the Aramaic language in the first half of the fifth century AD.

His most recent novel, Fardeqan – the Detention of the Great Sheikh, published by Egypt's Dar el-Shorouk, was short-listed for the 2020 International Prize for Arabic Fiction.