[1][2] Trujillo works with computer software and has examined the orbits of the numerous trans-Neptunian objects (TNOs), which is the outer area of the Solar System that he specialized in.

In late August 2005, it was announced that Trujillo, along with Michael Brown and David Rabinowitz, had discovered Eris in 2003.

in physics from the Massachusetts Institute of Technology in 1995, and was a member of the Xi chapter of Tau Epsilon Phi, and received his Ph.D. in astronomy from the University of Hawaiʻi in 2000.

As of 2016, Trujillo is assistant professor at the department of Astronomy and Planetary Science at Northern Arizona University.

[6] His numerous co-discoverers were: A D. C. Jewitt, B J. X. Luu, C J. Chen, D K. Berney, E D. J. Tholen, F M. E. Brown, G W. Evans, H S. S. Sheppard, J D. L. Rabinowitz, K A. Udalski, L M. Kubiak, M R. Poleski and N Glenn Smith.