An advocate of Romania's entering World War I on the side of the Allies, he was in Paris from 1917 to 1918, writing editorials in the French press and particularly in La Roumanie.

[1] After 1926, he became one of the most recognizable PNȚ leaders, the main figure of a pro-authoritarian faction bitterly opposed to left-wing groups such as those of Nicolae L. Lupu, Petre Andrei, Mihai Ralea, and Armand Călinescu.

"[4]The PNȚ subsequently repealed the 1926 laws preventing Carol from inheriting the Crown, and faced a constitutional crisis after Constantin Sărățeanu and Patriarch Miron Cristea resigned from the regency in protest.

[7] Nevertheless, Mironescu was to contribute to the appeal of fascism: his was the first in a series of governments that, faced with the Great Depression, reduced salaries for state employees, who soon began supporting the revolutionary solutions advanced by Codreanu.

[8] Other economic measures he took included contracting a foreign loan, ending export taxes on agricultural products and initiating a road-building project.

[1] In early 1943, during World War II, Mironescu was given a mandate to approach the leadership of Miklós Horthy's Hungary, in an attempt by Romania's Ion Antonescu to have both countries achieve a new territorial settlement and a common withdrawal from the Axis Powers (see also Romania during World War II); he began talks with Miklós Bánffy's delegation in Bucharest (June 9), but these negotiations ended when the two sides could not agree on a future status for Northern Transylvania, a region held by Hungary at the time.