A Marxist for much of his life, Mille was noted for his vocal support of peasant emancipation, for his early involvement with the Romanian Social Democratic Workers' Party (PSDMR), and his presence at the head of several magazines, culminating in his association with the moderate left-wing newspapers Adevărul and Dimineața.

After serving as an independent member of the Chamber of Deputies for one mandate (1899–1903), he aligned his views with those of Take Ionescu, and became a supporter of Romania's entry into World War I alongside the Entente Powers.

[3] Mille also began his association with the Iași-based socialist magazine Contemporanul, which carried a polemic with the established literary society Junimea,[1][2][4] and authored his first poems, collected in a "red notebook".

[5] He became one of the main figures in the Romanian students' left-wing circle of Paris — together with, among others, Alexandru Radovici, the future minister Mihai Săulescu, as well as Vintilă and Horia Rosetti (the sons of Radical leader C. A.

[5] Ultimately, Mille revealed that he was responsible for the whole affair (a notice published by Telegraful);[5] although Timpul did not reply, Mihai Eminescu, the influential poet who worked in the journal's mail room and reviewed all letters, later confessed to Zamfir Arbore that he had "given approval for print without reading them".

[7] According to Henri H. Stahl, during the late 1880s and early 1890s, Mille shared the vision of Vasile Morțun, Alexandru G. Radovici and Nădejde, which called on the socialist clubs to merge with progressive and radical forces such as George Panu's grouping.

[4] During the same period, Adevărul became involved in a heated debate with the literary magazine Vieața, after publishing an article in irreverent tone which referred to the writer and editor Alexandru Vlahuță as "a scoundrel".

[6] Taking over as editor-in-chief following Alexandru Beldiman's death in 1898, he led the paper into opposition to the PNL cabinet of Dimitrie Sturdza, who he argued had betrayed the generoși in his party by endorsing reactionary policies.

[9] In December, following the arrival to power of Gheorghe Cantacuzino and the Conservative Party, Adevărul investigated and denounced the practices of a French firm who had failed to respect its obligations involving public works in Constanța (see Hallier Affair).

[10] Also in 1899, the PSDMR disbanded, when a scandal was caused by the presence of socialist clubs in the countryside — of them, the PNL's Minister of the Interior Mihail Pherekyde claimed had been fermenting agitation, an accusation which met with protests from Mille and his Adevărul.

[12] During the large-scale Peasants' Revolt of 1907, he voiced criticism of the governing PNL for the violent manner in which it opted to repress protests,[9][10][13] and questioned the attitudes of former socialists who had joined the latter group (including Constantin Stere, who was serving as prefect).

"[10]Additionally, Mille's paper called for reparations to be paid to victims' families, for an amnesty to be declared, and for Vasile Kogălniceanu, an activist who supported the peasant cause and faced trial, to be set free; it also published the influential protest of Ion Luca Caragiale (1907 din primăvară până'n toamnă, "1907 from Spring till Autumn"), which questioned the establishment and policies of Romania.

[13][14] According to historian Anton Caragea, a confidential report of that year, presented to his superiors by the Austro-Hungarian Imperial and Royal Secret Service agent Günther, informed that Mille, as well as the editors of Universul and Epoca, had been advanced sums of money in order to exaggerate the amplitude of repression, and to incite both local and international outrage.

[15] Adevărul notably condemned the disadvantageous trade convention signed between Romania and Austria-Hungary, signaled that Romanians in the region were being subjected to violence, and alleged that the Austro-Hungarian state had included within its borders ridges of the Carpathians that it had no right to own.

[10] When an attempt on the life of PNL Premier Ion I. C. Brătianu, carried out by a certain Stoenescu, occurred in December 1909, authorities took the measure of arresting România Muncitoare editors, who were believed to be instigators of the attack.

[17] As the Romanian Campaign witnessed the occupation of Bucharest by the Central Powers, Mille and several of his collaborators took refuge in Iași, while other Adevărul journalists were arrested by German forces and deported to Bulgaria.