[3][4] Péter Mészáros was born in 1943 in Budapest, Hungary, and grew up in Liège, Belgium and Buenos Aires, Argentina, where he did his undergraduate studies.

[5] Mészáros is widely known in the astrophysical community for his papers on the relativistic fireball shock model of gamma ray bursts and their afterglows,[3][4] laying down the framework for the interplay between the jet dynamics and the external as well as internal shocks which determine the observational aspects of these sources.

He is also known in the cosmological community for the Mészáros effect,[2] or Mészáros equation, which quantifies the influence of dark matter in the evolution of the initial perturbations leading to large scale structures in cosmology.

He was active in the study of the interstellar medium as well as the astrophysics of black holes, and contributed broadly to the study of magnetized neutron stars, e.g.[6] He served as the science-theory lead of the NASA Neil Gehrels Swift Observatory space mission.

[12] He is currently a member of the Space Studies Board of the National Academy of Sciences.