Kathryn Hess was born 21 September 1967 in Bryn Mawr, Pennsylvania. She began to accelerate in mathematics in 1979, thanks to the Mathematical Talent Development Project (MTDP) set up in Eau Claire, Wisconsin, by her parents, through the Association for High Potential Children, which they also founded. Both programs are defunct at this point. Hess received her doctorate in mathematics from the Massachusetts Institute of Technology in 1989 under the direction of David J. Anick (de). Her dissertation was entitled A Proof of Ganea's Conjecture for Rational Spaces.[H91]
Hess received the Polysphere d'Or Teaching Award for her teaching at EPFL in 2013. In 2017, she was named a fellow of the American Mathematical Society for "contributions to homotopy theory, applications of topology
to the analysis of biological data, and service to the mathematical community". In 2017, she received an award as a distinguished speaker of the European Mathematical Society.