Lena Kjellén has a PhD from Uppsala University in Medical Chemistry. Her area of research is biosynthesis of glycosaminoglycans including physiological as well as pathological aspects. From 2001 she is professor in Medical Glycobiology at the University of Uppsala where she moved from the Swedish University of Agricultural Sciences. She has previously had an appointment as Professor II at Bergen University, Norway, and has also spent one and a half year in Birmingham, Alabama, USA during her years as a student. She is a teacher of biochemistry for medical and biomedical students at Uppsala University.

Since 2007 she is a member of the Royal Swedish Academy of Sciences. She is also a member of the scientific committee of NTA ("science and technology for all"), a programme for school development in science, engineering and mathematics, and represents the Royal Swedish Academy of Sciences in the ALLEA working group on Science Education.