Coustenis defended her PhD thesis in astrophysics and space techniques, "Titan's atmosphere from Voyager's infrared observations", at the Pierre and Marie Curie University (UPMC), Paris 7, in 1989, where in 1996 she went on to obtain a Habilitation to Direct Research (HDR).

From 2008 to the present, Athena Coustenis is director of research with CNRS, at LESIA at the Paris Observatory, in Meudon, France.

[5] Coustenis was in particular formerly the chair of ESA's Human Spaceflight and Exploration Science Advisory Committee (HESAC),[6] the president of the IUGG International Association of Meteorology and Atmospheric Sciences (IAMAS: 2011-2015) and of the ESA Solar System and Exploration Working Group (2010-2014).

Coustenis uses ground and space-based observatories to study Solar System bodies with emphasis on the satellites of the giant planets Saturn and Jupiter and exoplanets.

Her research in comparative planetology use the study of climate changes to further the understanding of long-term evolution on our own planet.

[8] She is science Co-Investigator in future missions like JUICE to the Jovian System and ARIEL for exoplanetary spectroscopic studies.