Loh teaches at Carnegie Mellon University, and from 2014 to 2023 served as the national coach of the United States' International Mathematical Olympiad team.

He attended James Madison Memorial High School, and in 1999 won a silver medal representing the US in the International Mathematical Olympiad (IMO).

[8] Loh pursued graduate studies in mathematics at Princeton University with the support of a Hertz Fellowship,[7] and, under the supervision of Benny Sudakov, received a Ph.D. in 2010 with his dissertation Results in extremal and probabilistic combinatorics.

[19] Loh is the founder of Expii, a crowdsourced math lesson and problem solving website with tens of thousands of users.

They developed NOVID, a contact tracing app with the unique feature of notifying users before exposure, whenever someone in their social network is affected, rather than after.

[4] NOVID tracks infections anonymously using location information gathered from inter-communicating cell phones,[22] and was tested in pilot studies on college campuses.