Dr Alderslade has worked in public health, national and local health administration, research and higher education in the United Kingdom, and for twenty-five years in humanitarian and development international health with the World Health Organization. He holds the degrees of MA. BM. BCh. (Oxon) and is a Fellow of the Royal College of Physicians of London (FRCP) and the Faculty of Public Health (FFPH), both in the United Kingdom.

His United Kingdom work included five years working with the UK Medical Civil Service, including a Senior Medical Officer appointment as Private Secretary to the Chief Medical Officer; ten years working in public health within the National Health Service as a Consultant in Public Health Medicine and Regional Director of Public Health; three years as a manager of community health services; and one year as a Professor of Community Care.

Internationally he has worked in humanitarian and development positions with the World Health Organisation’s Regional Office for Europe, including five years managing all the Office's humanitarian programs within the Region. He then  with the European Union and the United Kingdom Department for International Development in Romania, acting as Adviser to the Romanian Prime Minister on the development of child protection services in Romania. He was for 4 years Senior External Relations Officer at the World Health Organization’s Office at the United Nations in New York. 

Between 2010 and 2012 he was Senior Adviser in Health Policy at the World Health Organization’s Regional Office for Europe in Copenhagen, Denmark, working on the strengthening of public health capacities and services across the European Region, and a new health policy framework for the Region, Health 2020. He continues to act as an Adviser to WHO’s Program on Health and Migration.  

Dr Alderslade also teaches public and global health subjects at New York University in the United States.