[1][2] While studying at the Baltic State Fishing Fleet Academy, Kashin wrote for Komsomolskaya Pravda in Kaliningrad where he expressed rather sharp views.

After a while, he left the newspaper, became a staff writer at Kommersant and became the leading Russian journalist covering youth political movements, ranging broadly from the National Bolshevik Party to Nashi.

[citation needed] In 2011, Kashin was present at the meeting with then US Vice President Joe Biden, as part of a group of Russian public figures.

After moving to London in April 2016, Kashin has successively worked for Echo of Moscow (as a guest host), Republic.ru (as an exclusive columnist), Komsomolskaya Pravda Radio (as a co-host to Maria Baronova).

[15] President Dmitry Medvedev said that the assailants "must be found and punished" and instructed Prosecutor-General Yuri Chaika and Interior Minister Rashid Nurgaliyev to take special control over the investigation of the attack.

In March 2013, Kashin participated in single pickets in support of Pussy Riot members Nadya Tolokonnikova and Maria Alyokhina.

[24] Considering the widely publicized case of Andrey Sychev, in which a young conscript lost his legs and genitalia after brutal beating by other servicemen, Kashin claimed that the case was fabricated by Committee of Soldiers Mothers: "The only proven episode... is that Sychev squatted for a while in front of now imprisoned junior sergeant Sivyakov.... All the other stuff was thought up by the chairman of Chelyabinsk Committee of Soldiers Mothers Lyudmila Zinchenko, who, after giving a dozen of interviews to liberal media now cowardly conceals from investigators.

[37] In May 2024, Mikhail Khodorkovsky, a former Russian oligarch and opposition leader, in the context of a conflict with associates of Alexei Navalny over the release of the documentary "The Traitors" on the events of the 1990s, posted on social media that he was willing to provide "financial support for a judicial dispute to anyone who was unjustly accused."

Kashin responded with an open letter, criticizing Navalny's allies and requesting Khodorkovsky's assistance in organizing a defamation trial.

The letter stated that Mr Kashin had been included on the list of individuals targeted by the International Anti-Corruption Foundation due to a dispute with the organization's leadership, with the official reason being a pre-conflict post urging others not to forget "who our people are" (the publication was actually published after large-scale events had begun).

[40] A heavily fictionalised version of Kashin played by Yevgeny Stychkin appears as one of the protagonists in the Russian journalistic procedural mini-series Just Imagine Things We Know.