Hanna received M.D. and Ph.D. degrees in 1997 from the University of Helsinki, Finland. Hanna became interested in blood cell development during her early years of medical school, and did her graduate thesis with Aarno Palotie and Leena Peltonen-Palotie on defining genetic defects in a congenital bleeding disorder, Factor XIII deficiency. Hanna's interest in hematopoietic stem cell (HSC) biology started during her post-doctoral training in Stefan Karlsson's laboratory in Lund University, Sweden, (1998-2000), where she developed lentiviral gene transfer tools to manipulate stem cells. In 2000, Hanna joined Stuart Orkin's group at the Dana-Farber Cancer Institute, Harvard Medical School. Her work in Boston focused on hematopoietic transcription factors, as well as on defining the first stages of HSC development through identifying markers for nascent HSCs and describing the placenta as a novel site where HSCs develop.

Hanna joined UCLA as an Assistant Professor in the Department of Molecular, Cell and Developmental Biology (MCDB) in July 2005. She is an active member of the Eli and Edythe Center for Regenerative Medicine and Stem Cell Research (BSCRC) and Jonsson Comprehensive Cancer Center (JCCC) Gene Regulation and Hematopoietic Malignancy Program areas. Hanna received the Martha Austin Research Award from the Stop Cancer Foundation in 2005, and Junior Faculty Scholar Awards from the American Society of Hematology (ASH) and V foundation for Cancer Research in 2006. Her lab has also received support from NIH/NIDDK, Harvard Stem Cell Institute (HSCI), Cancer Research Coordinating Committee (CRCC) and California Institute for Regenerative Medicine (CIRM). In addition to supervising her research team, Hanna teaches undergraduate and graduate students at UCLA, and has launched a new Stem Cell Biology Course (MCDB 168) for upper division undergraduates. Hanna feels very much at home at UCLA and LA, and appreciates the sun, flowers, the ocean. If Hanna is not in the lab, she is most likely riding her horse Cera.