Rosling was born in Uppsala, Sweden. From 1967 to 1974 Rosling studied statistics and medicine at Uppsala University, and in 1972 he studied public health at St. John's Medical College, Bangalore. He became a licenced physician in 1976 and from 1979 to 1981 he served as District Medical Officer in Nacala in northern Mozambique.
On 21 August 1981, Rosling discovered an outbreak of konzo, a paralytic disease, and the investigations that followed earned him a Ph.D. degree at Uppsala University in 1986. He spent two decades studying outbreaks of this disease in remote rural areas across Africa and supervised more than ten Ph.D. students. Outbreaks occur among hunger-stricken rural populations in Africa where a diet dominated by insufficiently processed cassava results in simultaneous malnutrition and high dietary cyanide intake.
Rosling's research has also focused on other links between economic development, agriculture, poverty and health in Africa, Asia and Latin America. He has been health adviser to WHO, UNICEF and several aid agencies. In 1993 he was one of the initiators of Médecins Sans Frontières in Sweden. At Karolinska Institutet he was head of the Division of International Health (IHCAR) from 2001 to 2007. As chairman of Karolinska International Research and Training Committee (1998–2004) he started health research collaborations with universities in Asia, Africa, the Middle East and Latin America. He started new courses on Global Health and co-authored a textbook on Global Health that promotes a fact-based world view.
Rosling presented the television documentary The Joy of Stats, which was broadcast in the United Kingdom by BBC Four in December 2010.