Such a sentence would keep Navalny in prison until after the next presidential election, scheduled for 2018.
In closing arguments, Navalny, who spoke in his own defense, compared his trial to a "television series" built on "fantasy and fairy tales," RFE/RL's Russian Service reported.
He vowed to "do everything we can to destroy this feudal system in Russia" and accused the country's connected elite of "sucking the blood from Russia."
His nine-minute indictment of the system that has emerged in the decade since Vladimir Putin emerged as the dominant political force was met with scattered applause in the Kirov courtroom.
Judge Sergei Blinov said he would deliver a verdict on July 18.
The vocal Kremlin critic is accused of stealing the equivalent of $510,000 from the Kirovles lumber company while working as an adviser to the governor of Kirov Oblast in 2009. That governor, Nikita Belykh, has testified that he saw no signs of wrongdoing by Navalny.
The defendant called the charges "absurd" at a mid-June hearing, and has insisted the prosecution is politically motivated.
In his closing argument, Navalny condemned "this system of power in which 83 percent of the country's wealth is in the hands of half of one percent of the population."
He added that "anyone who stands aside will just be helping the disgusting feudal system that sits like a spider in the Kremlin, the 100 families who are sucking the blood from Russia."
WATCH: Aleksei Navalny delivers his closing arguments, in which he condemns his trial and the system that produced it (in Russian):
Navalny allies continue to push back in defense of the figure who shot to prominence as an anticorruption gadfly and took on a leadership role amid the protests that followed the 2011 Duma and 2012 presidential elections.
The Coordination Council of the Russian Opposition announced on June 18 that it supported his nomination by the Parnas party as a candidate for the Moscow mayoral post in the coming September elections.
Putin, who has already served two terms as president and began a third in early 2012, after a four-year tenure as prime minister, is eligible to run for a fourth term in the Kremlin in the scheduled 2018 vote.