He served as ambassador (2019 to 2022) to Canada prior to joining Johns Hopkins University as a Senior Fellow for the Foreign Policy Institute (SAIS).

He has written and co-authored a considerable number of articles on general subjects ranging from International Law and Human Rights to Mexico’s foreign relations and policy.

[3] From August 2009 until December 2013 he was appointed Permanent Representative of Mexico to the United Nations and other international organizations based in Geneva, Switzerland.

[3] During his posting as the permanent representative of Mexico to the UN and other International Organizations in Geneva he had a prominent role in "landmark agreements"[4] and multilateral negotiations such as the World Health Organization Pandemic Influenza Preparedness Framework (PIP), WIPO's Marrakesh VIP Treaty to Facilitate Access to Published Works for Persons who are Blind, Visually Impaired, or otherwise Print Disabled[5] and the creation of the first special procedure within the UN Human Rights Council on the elimination of discrimination against women in law and practice.

He resigned from the post in May 2022 to take up a professorship at the Paul H. Nitze School of Advanced International Studies at Johns Hopkins University.