Former governor of Russia's eastern Khabarovsk region, Sergei Furgal, was sentenced to 22 years in prison on Friday.
He was convicted of attempted murder and ordering contract killings of business rivals.
Furgal denied the charges.
Earlier this month, a jury found the former governor guilty of organizing two murders and one attempted murder.
Russia's prosecutor general's office said: "The court established that Furgal and his accomplice, guided by selfish motives and a desire to increase the income of a commercial organization controlled by him ... created an organised group in 2004 to commit murders of competitors."
One of Furgal's lawyers, Boris Kozhemyakin, said the verdict was "unlawful" and his team would seek an appeal.
Who is Sergei Furgal?
The 2020 arrest of the popular governor sparked a wave of protests in the Khabarovsk region.
Local media reported at the time that the demonstrations were largely peaceful and led to no arrests. The Agence France Presse (AFP) news agency said that one march in Khabarovsk drew a crowd of tens of thousands of people, with smaller demonstrations being held in Komsomolsk-on-Amur, Elban, Solnechny and other cities.
He was accused of committing the crimes in 2004 and 2005, when he was a prominent businessman in far eastern Russia.
Furgal's supporters claim that the charges were politically motivated.
The former governor won a surprise election victory in 2018 on a ticket for the ultra-nationalist Liberal Democratic Party, securing 70% of the vote. The record win ousted longtime incumbent Vyacheslav Shport, who is a member of President Vladimir Putin's United Russia Party.
Putin fired Furgal days after the former governor's arrest, citing "loss of trust."