John’s research focuses on European company law and corporate sustainability. His work has been published across many international peer-reviewed journals including Transnational Legal Theory, the Journal of Corporate Law Studies and Law, Innovation and Technology. His book - The Societal Company: Sustainability, Shareholder Value and European Company Law - was published by Hart in 2025.

John also writes widely on Irish company law and has had articles published in the Jurist, the DULJ, the Irish Judicial Studies Journal and contributes a yearly chapter to the Annual Review of Irish Law (Round Hall). His research has been cited widely in academic journals, in textbooks and by the Irish Supreme Court and Court of Appeal.

John teaches company law across several undergraduate programmes and has taught commercial law at undergraduate and postgraduate level. He is a former chair of the LLM programme and led the development of the Masters in Data Protection and Privacy, chairing the programme from 2021-24. He is an Advance Higher Education Fellow and is a member of the executive council of the Irish Association of Law Teachers.

John has worked with the European Commission on a report on corporate transparency (2023) and with the Irish Law Reform Commission on a report on corporate offences (2018). He is a visiting scholar at Queen’s University Belfast and previously held visiting positions at the College of Europe and Chulalongkorn University.