Before that professor Puska was the Director for Noncommunicable Disease Prevention and Health Promotion at the World Health Organization Headquarters in Geneva.  His previous work in Finland and internationally was strong background when he helped WHO to upgrade its work to respond to the rapid increase of chronic noncommunicable diseases (NCDs) in many parts of the world.  According to the latest statistics NCDs are responsible for about 60% of all deaths.  A vast majority of these deaths are in the developing world where these diseases, and their risk factors, are moving to poorer counties and within population to the lower socioeconomic parts of the population.

At WHO, Pekka Puska directed the work on integrated prevention of NCDs targeting the main risk factors (tobacco, unhealthy diet and physical inactivity) through broad health promotion, national programmes, policy measures and regional networks. Increased attention was paid on broad collaboration, with a number of partners, including those within the UN Organization. Professor Puska's Department also worked on school health & youth health promotion, ageing and life-course, health behaviour surveillance, oral health, evidence in health promotion etc.

In 2002 the 55th World Health Assembly requested the WHO’s Director-General to prepare a Global Strategy on diet and physical activity, as well as support an annual Move For Health Day as a continuation of the successful World Health Day 2002.  Professor Puska’s Department was the focal point of these activities that culminated in adoption of the Global Strategy on Diet, Physical Activity and Health by the World Health Assembly in 2004. The Department also coordinated the global Mega Country Health Promotion Network as well as the regional NCD prevention networks linked by a WHO Global Forum on NCD Prevention and Control.  In these two networks, the work combined national policy development, targeting main risk factors such as unhealthy diet, tobacco and physical inactivity, with broad health promotion and health service work.  Practical programmes at WHO included the global QUIT AND WIN (Smoking cessation campaign), coordinated by KTL in Finland.

Before joining WHO, professor Puska has, for most of his career, worked at the National Public Health Institute as Director of the Department of Epidemiology and Health Promotion. He was, for 25 years, the Director and Principal Investigator of the North Karelia Project: prevention of cardiovascular diseases in the province and later on in all Finland. Within 25 years, about 80% decline in annual heart disease mortality among the working age population and a dramatic general improvement in public health took place.  The project is widely seen as a model for successful population based prevention of cardiovascular and other noncommunicable diseases.

Professor Puska has, internationally, been involved in a number of scientific, expert and public health functions e.g. scientific conferences, WHO's expert work, international consultations, multinational research projects etc. He has over 400 scientific publications in the field of epidemiology, preventive medicine, health promotion and public health.

Professor Puska has served as a Member of the National Parliament of Finland, as well as the Elector of the President of the Republic. He has also served as chairman of the Finnish Centre for Health Promotion, has chaired the Scientific Committee of the World Health Education Conference in Helsinki in 1991, and the International Steering Committee of the 12th World Conference on Tobacco or Health, held in Helsinki, Finland in 2003. Currently he chairs the Organizing Committee of the International Conference of Diabetes Prevention, to be held in Helsinki in 2008.

In this current position as Director General of the National Public Health Institute (KTL) professor Puska has a central position in Finnish public health work and health policy, while he also maintains a number of international commitments. Among other things, he is currently the chair of National Nutrition Council, the President of Finnish Heart Association and chair of the Board of the UKK Institute for health promotion.

Professor Puska is the Vice-President of the newly established International Association of National Public Health Institutes (IANPHI). The association links the national public health institutes of the world and helps countries to establish or develop their institutes to strengthen the national public health infrastructure. Professor Puska has also represented Finland in the Governing Council of the WHO International Agency for Cancer Research (IARC) since 2004.