[1][2][3] Mitrokhin studied at the Moscow State Pedagogical University and got his PhD in political science.

Together with Grigory Yavlinsky, Alexei Yablokov, Sergei Ivanenko, and Igor Artemyev, he joined the party's political committee.

On 11 June 2009, Mitrokhin handed over the anti-crisis plan developed by Yabloko to President Dmitry Medvedev.

[7] In the Moscow City Duma elections in July 2009, Mitrokhin headed the Yabloko list.

"[10] On 22 January 2010, at a meeting of the State Council of the Russian Federation, he accused United Russia of monopolizing the party system.

On 14 January 2013, Mitrokhin approved the exit of 13 members of the St. Petersburg branch from the party, including three deputies of the Legislative Assembly: Olga Galkina, Maxim Reznik, and Vyacheslav Notyag.