As a Conservative policymaker and disciple of Alexandru Marghiloman, he rewrote legislation on education reform and brought the Romanian Orthodox Church under the control of its high clergy.

His participation in the Marghiloman government recovered for Romania the region of Bessarabia, but the subsequent return of Ententist forces made him a political suspect.

[5] Upon his return to Romania, he was made Cabinet Secretary of Foreign Minister Vasile Boerescu, then head of Political Affairs, but left in 1881 to set up legal practice.

He received tenure in 1913,[6] and became editor of the academic journal, Revista Critică de Drept, Legislație și Jurisprudență ("Critical Review of Law, Legislation and Jurisprudence").

During 1886, Arion, Take Ionescu and Nicolae Fleva were the main "United Opposition" agitators who tried to seal a pact with the Junimea conservatives, in an effort to topple the National Liberals.

As Junimist poet-critic Mihai Eminescu once wrote, the Arion brothers were "the runts, the intellectual and moral plebs, ... everything basest and most degraded that one can expect to find in the cities of the Romanian nation".

From 1896, he was president of the national school and public libraries board (Casa Şcoalelor), where he employed the services of poet George Coșbuc.

Arion represented the civil party, Aurelia Stelorian, whom Georgescu had assaulted with acid; his adversary in court was another famous lawyer, Barbu Ștefănescu Delavrancea.

He sacked Haret's favorites and replaced them with Junimea men, but also introduced legislation which made bureaucratic office incompatible with a teaching position.

He personally intervened to ensure the full-time employment of aspiring jurists, including Paul Negulescu and his own nephew, Ion Peretz.

[16] Arion's mandate witnessed another outbreak of civic disobedience, this time centered on the public cult of liberal symbols, including images of Domnitor Alexander John Cuza.

The "Arion Law", adopted by Parliament in 1912, established clear criteria for the promotion of teachers and academics, ensuring greater professionalization: teaching positions were granted on the basis of a solid scientific reputation in the respective field of expertise.

[16] Under a National Liberal government, Romania remained a neutral country, a policy that was welcomed by the senior, "Germanophile", Conservatives: Carp, Maiorescu, Marghiloman.

[24] Constantin's brother Virgil and his son, Dinu (who was secretary of the Conservative Study Circle) shared his ideas on national politics.

[25] Following the German advance into southern Romania, C. C. Arion remained behind enemy lines, in Bucharest; the National Liberal cabinet and its Filipescu Conservative backers had relocated to a temporary home in Iaşi.

[24] He frequented the Germanophile circle of Raymund Netzhammer and Marthe Bibesco, with whom he discussed the idea of granting the Romanian throne to a Habsburg-Lorraine prince.

[26] Virgil Arion was a more radical Germanophile: he agreed to take over as Minister of Public Instruction in the puppet government of Lupu Kostaki, answering to the occupiers.

[29] He was privately enthusiastic about the turn of events, since he believed that Romania would recover at the same time some of its irredenta, claimed from the Russian Republic, and the territories held by the Central Powers.