Shaila-Ann Rao has returned to the FIA as an interim replacement for Peter Bayer, who is departing from his roles as secretary-general and F1 executive director.
Bayer had served as secretary-general since 2017 and had been responsible for the financial management of the FIA and all of its operational departments.
Last year, Bayer stepped into the new role of F1 executive director and oversaw the departure of Michael Masi from his post as race director earlier this year in the wake of the Australian's controversial handling of the Abu Dhabi Grand Prix.
Bayer's exit comes as a surprise given he only took up the executive director role in December.
An FIA statement read: "The FIA warmly thanks him for the achievements he has contributed to the development of motorsport over the last five years.
"In particular, he has supervised, with the entire Sport Division, the building of the single-seater pyramid from karting to F1, the creation of the new World Rally-Raid Championship, as well as improving safety and sustainability in all disciplines.
"The FIA wishes him all the best for the future."
Bayer is to be replaced on an interim basis by Rao, who has just returned to the FIA after three and a half years with Mercedes.
Rao, who previously held the position of FIA legal director from mid-2016 to the end of 2018, served as general counsel to Mercedes before taking on the role of special advisor to team principal Toto Wolff.