His research focuses on mathematical biology and medicine, specifically the combination of nonlinear dynamics, the theory of stochastic processes, and computational science, to better understand disease mechanisms and develop relevant treatment strategies, including drug and digital medicine for sleep disorders.

Upon reading a news article about using math to study heart disease, it lead him to the University of Michigan as it was known for mathematical biology.

[12] He also worked as an associate member at the Korea Institute for Advanced Study from 2018 and then as a visiting scholar in the Department of Mathematics in the University of Michigan from 2019 to 2020.

The Intracellular Dynamics Team develops reduction methods for multi-scale stochastic systems and identifies molecular mechanisms underlying robust circadian rhythms.

[17] Despite temperature changes, Kim found a mathematical model which underlies a molecular mechanism for regulation of the circadian clock.

[21] Kim was the first to propose and then prove multiple results in justifying the stochastic quasi-steady state approximation (QSSA).

The new formula is based on an improved mathematical foundation and can accurately predict drug metabolism rates without artificial factors.

When tested, the new formula predicted drug interactions accurately 80% of the time compared to 38% with the equation in FDA guidance.