[1] Aguirre is a professor and holds the Faggin Presidential Chair for the Physics of Information at the University of California, Santa Cruz.

[4][5][6][7] In 2015, he co-founded the aggregated prediction platform Metaculus with Greg Laughlin.

In 2019, he published the pop science book Cosmological Koans.

[1][2] His research has focused on various topics in theoretical physics including early universe, inflation, the foundations of quantum mechanics, foundations of statistical mechanics, gravity physics, first stars, the intergalactic medium, galaxy formation and black holes.

[11] Together with Max Tegmark he developed the cosmological interpretation of quantum mechanics.