In 1996, Krasheninnikov received his doctoral degree in juridical sciences by defending a thesis "Modern issues of ownership and other property rights in residential premises" in Moscow State University.

Since 1999 he has been a Deputy of the State Duma,[5] at first representing Union of Right Forces, later joining United Russia.

He claimed that it would be easier for him to implement liberal reforms as part of the party of power, rather than through external factions.

After being re-elected in 2003, Krasheninnikov chaired the reformed Committee on Civil, Criminal, Arbitral and Procedure Legislation.

In 2020, Krasheninnikov was appointed co-chairman (along with Senator Andrey Klishas and academician Taliya Habrieva) of the working group on the preparation of proposals for amendments to the Constitution of Russia.

In 2021, Krasheninnikov and Klishas introduced a law to harmonize regional authorities across all federal subjects of Russia, which has expanded the grounds for removing governors who have lost the confidence of the President and has removed the federal ban on governors holding office for more than two consecutive terms.

[10] In 2022, against the backdrop of the Russian invasion of Ukraine, Krasheninnikov, Klishas, and Irina Pankina proposed a law that would exempt certain categories of convicted individuals and those who have committed minor or moderate crimes from punishment if they join the military during times of mobilization, martial law, or wartime.