An alumna of Sciences Po and the École nationale d'administration, Parly was appointed Secretary of State for the Budget on 3 January 2000 in the government of Prime Minister Lionel Jospin.

[8] Shortly after taking office, Parly ordered an investigation into allegations brought forward by the satirical weekly Le Canard enchaîné that the acting head of the French Air Force borrowed a Dassault/Dornier Alpha Jet on weekends to fly from his base in Bordeaux to his home in Provence.

[9] In 2020, Parly placed a French lieutenant colonel, based in Italy and stationed with NATO, under investigation over a suspected breach of security after having passed sensitive documents to the Russian secret services.

[20][21] Parly's tenure as Armed Forces Minister was marked by the 2021 Tribune des généraux published in Valeurs actuelles, which spanned talk of a coup d'état after tens of retired army officers openly criticised Macron's leadership in the fight against Islamism and warned of a possible civil war.

[22][23] In 2022, Parly led talks with Ministry of Defense Prabowo Subianto over Indonesia´s decision to order 42 Dassault Rafale fighter jets in a $8.1 billion deal, making Jakarta the biggest French arms client in the Indo-Pacific region.