Päivi Lähteenmäki graduated from the Medical School at the University of Turku in 1984, where she also specialized in Pediatrics and PediatricHematology and Oncology. She defended her thesis in 1999 on Effects of childhood cancer on patients and their families - physical and psychosocial aspects. She worked in 2002 as a post-doc Clinical and Research Fellow at Bristol Sick Children’s Hospital BMT Unit, Bristol, UK. Subsequently, she has worked as a Consultant at the Department of Pediatrics, University of Turku. Since 2008, she has been Docent (Adjunct Professor) of Pediatric Hematology and Oncology at the Faculty of Medicine, University of Turku, and Head of the Division of Pediatric and Adolescent Hematology/Oncology at Turku University Hospital in Turku, Finland. Currently she works also as the Chief of the Swedish Childhood Cancer Registry at Karolinska Institutet in Stockholm, Sweden.

During the years, Päivi Lähteenmäki has served as the chairman or a board member of the Nordic Society of Pediatric Hematology and Oncology as well as the Finnish Association of Pediatric Hematology and Oncology. In 2012-2014, She was the chair of a group planning the establishment of childhood cancer late-effect clinics in Finland. In 2016, she was awarded the Finnish Cancer Association Price, Oncologist of the year in Finland.