Dreyer received his Ph.D. in quantum gravity in 2001 from the Pennsylvania State University[1] under the direction of Abhay Ashtekar.

[2] Subsequently, he has held a postdoctoral fellowship at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, a Marie Curie Fellowship at Imperial College, London, and a postdoctoral fellowship at the Center for Theoretical Physics, Massachusetts Institute of Technology.

In 2002 Dreyer proposed[3] a connection between the Barbero-Immirzi parameter in loop quantum gravity and the asymptotic behaviour of black hole quasinormal modes (in numerical general relativity), building on previous insights due to Shahar Hod.

[4] Subsequently, Lubos Motl proved that the exact asymptotic behaviour of the quasinormal modes of the Schwarzschild black hole was as predicted numerically.

[5] Dreyer has developed an approach to quantum gravity known as "internal relativity".