In 1974, he was an assistant, then senior lecturer at the Department of Higher Mathematics of the Leningrad Polytechnic Institute (now - Saint Petersburg State Technical University).

He also participated in lawsuits “The labor collective of the Soyuzproektverf Institute against the Committee for the Management of City Property of St. Petersburg”, “Yabloko” against the Central Election Commission” (on invalidating the decision to refuse to register an electoral association).

He was a member of a special commission of the State Duma to assess compliance with procedural rules and the factual validity of the charges brought against Russian President Boris Yeltsin.

He spoke with a dissenting opinion, believing that on two counts (in connection with the commission of actions that led to the weakening of the defense capability and security of Russia; in connection with the commission of actions that led to the genocide of the Russian people), bringing the president to criminal responsibility is contrary to the Criminal Code of Russia.

And on one point (in connection with the events of September–October 1993 in Moscow), the question of whether the resolution adopted by the State Duma of 23 February 1994 “On declaring a political and economic amnesty” hinders the filing of charges.

He managed to prove that due to the underfunding of a number of federal programs in St. Petersburg, his rights were violated, since the ministry did not allocate the funds approved in the budget for the restoration of the metro line, torn as a result of erosion, for the construction of flood protection structures in the Gulf of Finland, for the construction of the Hermitage storage fund and the new building of the Russian National Library.

In 2003, Popov was again elected to the State Duma of the fourth convocation in the same district, and was nominated by the Yabloko party, but was not included in the registered deputy associations.