Dr. Ernst obtained a B.S. in Biochemistry at University of Washington in Seattle, then a Ph.D. in Microbiology and Immunology at the University of California, Los Angeles. This was followed by post-doctoral studies with Dr. Korsmeyer first in St. Louis then moving with the lab to complete her studies at the Dana Farber Cancer Institute. She then took a faculty position at Dartmouth Medical School in 2004 where she became a Co-Director of the Cancer Mechanisms Program in the NCI-designated Norris Cotton Cancer Center. In 2014, she was recruited by the University of Colorado, Denver (now Anschutz Medical Campus) Section of Hematology/Oncology/Bone Marrow Transplant in the Pediatrics Department together with the Pharmacology Department. She served as Associate Director of the MSTP from 2017-2023 and continues to serve as co-leader of the Molecular Oncology Program within the University of Colorado Comprehensive Cancer Center since 2020. Her lab focuses on epigenetic mechanisms regulating normal hematopoiesis and leukemia focusing on MLL-family histone methyltransferases.

Dr. Ernst is the Postle Family Chair in Pediatric Cancer and Blood Disorders at Children's Hospital Colorado, a Cancer Center and Gates Institute member.

For graduate training, Dr. Ernst is a member of the MSTP; Cancer Biology; Molecular Biology; Immunology; Cell Biology, Stem Cells and Development; and Biological Sciences Programs.