Howard Mann was appointed as an Associate and Senior International Law Advisor to IISD in 1998.

From 2003-2009, he initiated and managed IISD’s Investment and Sustainable Development program. Howard has worked with colleagues in advising and training government officials from over 80 developing countries on international investment law issues, investment treaty negotiations, and the development of sound investment policy from a sustainable development perspective.

Howard was the lead author of IISD's Model International Agreement on Investment for Sustainable Development, significant portions of which have been adopted in multiple international investment treaties since it was published in 2005. He represented IISD in its precedent-setting amicus curiae intervention in the NAFTA case between Methanex Corp. v. the United States, the first international investment arbitration to allow interventions by civil society organizations. More recently, Howard was a leading participant in the preparation and drafting of the first internationally recognized model contract on mining from a sustainable development perspective, the Model Mine Development Agreement of the International Bar Association. Howard has served on two Government of Canada advisory committees on international trade and investment law, a special expert panel for the International Commission of Jurists on corporate complicity in human rights violations, advised on the development of the UN Principles on Business and Human Rights.

From 1988 to 1993, Howard was a lawyer for the Government of Canada and was actively involved in the negotiation of several international environmental agreements, including climate change and the NAFTA environmental agreement. He also participated in several cases heard in the Supreme Court of Canada. From 1993-1999, Howard maintained a full-time practice in international law, where his clients included the government of Canada, international organizations, national and international non-governmental organizations. Howard has been an Adjunct Professor of international law at the University of Ottawa’s Faculty of Law, is widely published in his areas of specialization, and is a frequent speaker at international conferences.