Dean has worked worldwide for the past thirty years, across Africa, the Americas, and globally, to prevent violence, promote peace, advance gender equality and human rights, and strengthen organizational capacity.​

In his work, he has established and led initiatives locally, nationally, and globally, creating strong civil society groups and partnerships. This includes the founding of Sonke Gender Justice, a multi-award winning, high-impact South African NGO working from six offices in South Africa and in twenty-five countries in Africa to promote gender equality, prevent sexual and gender-based violence (SGBV), advance children’s rights, and reduce the spread and impact of HIV and AIDS. ​

Additionally, he has partnered with numerous United Nations agencies, including UNFPA, WHO, UN Women, UNHCR and UNDP, to enhance workplace culture, align values, promote diversity, equity, inclusion, and address problems like bullying and gender inequity. His work has included assessments and analysis of current programs and their community impact, advising in the development and delivery of training, culture surveys, leadership development and coaching, and strategic support. ​

Dean has extensive expertise SGBV and is published widely on SGBV and gender equality in influential media outlets and in prestigious peer reviewed journals, including the Journal of Violence Against Women, the Lancet, the Journal of Gender and Society, the Journal of the American Public Health Association, amongst others. He has also been involved in numerous UN Expert Group Meetings and advisory committees. ​

Dean works closely with many academic institutions, designing courses, conferences and symposia, and mentoring many graduate students. In addition to current honorary appointments at the University of Cape Town and the University of San Diego Joan B. Kroc School of Peace Studies, he has previously served as a Research Fellow at the Gender Violence and Health Centre at the London School of Hygiene and Tropical Medicine, a Research Analyst at the UCLA Program in Global Health, and was a visiting scholar at the UCSF Center for AIDS Prevention Studies. He has given lectures at Harvard, Columbia, New York University, Johns Hopkins, UC Berkeley, UCLA, amongst others.​

Dean is an Ashoka Changemaker Fellow and currently serves on the International Gender Equality Prize jury, advising the Prime Minister of Finland on their annual award selection.