Hossein teaches real property law, trusts,law of the sea, energy and environmental security and international law. He joined Flinders University in 2005, after seven years of teaching at UNSW, the University of New England, and Western Sydney University.

His current research interests include Australian perspectives on international and comparative law particularly with regards to global energy, resources and the environment as well as Islamic and Middle Eastern law.

Hossein has authored, co-authored, and edited five scholarly books, including The Legal Regime of Offshore Oil Rigs in International Law (Ashgate Publisher, 2001) and The Boundaries of Australian Property Law (Cambridge University Press, 2016). He has published in leading international law journals worldwide. He has been a Co-Rapporteur of a committee of the International Law Association (since 2011) and serves on the editorial boards of a number of law journals in Australia, Asia and Europe.