Beginning in 1997, Dengin worked as a teacher at the Obninsk Center of Extracurricular Activities and later in the youth wing of the Liberal Democratic Party of Russia.

In 2004, he graduated from the Moscow State University of Economics, Statistics, and Informatics.

He was a candidate for the Governor of Kaluga Oblast on behalf of the Liberal Democratic Party of Russia on 13 September 2015 gubernatorial election [ru].

[2][3] Dengin has spoken strongly in favor of expanding the regulative powers of the Federal Service for Supervision in the Sphere of Telecom, Information Technologies and Mass Communications (Roskomnadzor) over the internet.

[4] In October 2015, Dengin, and fellow deputies Aleksandr Yushchenko [ru] of the Communist Party and Vadim Kharlov [ru] of A Just Russia, introduced an amendment to the Administrative Code which would have obliged media organizations to disclose foreign funds to Roskomnadzor within 30 days.