Later he studied in graduate school of the Leningrad State University Faculty of Law along with Dmitry Medvedev.

On 3 March 2010, the Federation Council appointed Aranovsky the judge of the Constitutional Court of Russia[1] after he had been nominated by President Medvedev.

During his service in the Russian Constitutional Court, Aranovsky wrote several dissenting opinions on high-impact cases such as cases of the attorney-client privilege, on the right of persons with dual citizenship to own the media, on the admission of probationers to the elections (to which Alexei Navalny referred in his 2018 presidential campaign) and on the higher education system in Russia.

In 2019 Aranovsky claimed that the USSR was an "illegally created state" and the Russian Federation should not be considered the successor of the "repressive and terrorist acts" of the Soviet government.

Aranovsky currently serves as a professor at the Department of Public Law of the State Academic University for the Humanities in Moscow.