"It can be assessed differently, but it was a heavy load," Medvedev said, adding that he will invite Gorbachev to the Kremlin to give him the award.
Gorbachev has been revered in the West for his liberal reforms that led to the collapse of Communism, but he has been reviled at home, where many hold him responsible for the breakup of the Soviet Union and the ensuing economic meltdown that cost many most of their lifetime savings.
His bitter rival, the late Boris Yeltsin, Russia's first president, treated Gorbachev in a humiliating way, giving him just a few hours to pack up after he resigned as the Soviet president on Christmas Day 1991. Yeltsin also issued Gorbachev a government pension equivalent to only a few dollars a month.
Gorbachev attended Yeltsin's funeral in 2007 in a gesture of reconciliation, but has remained scathingly critical of Yeltsin's legacy.
Gorbachev recently has started getting at least some recognition as an elderly statesman, including a large photo exhibition on his years in power in a prestigious hall just outside the Kremlin. But it wasn't until Wednesday that he received a top award from the state.
Gorbachev has become increasingly critical recently of Russia's current rulers -- especially Prime Minister Vladimir Putin -- saying they have rolled the country back to the old Soviet ways.
He has described Russia as an "imitation" of democracy, where both parliament and the courts lack independence from the government and the main pro-Kremlin party is a "bad copy" of the Communist Party of the Soviet Union.
Gorbachev also has harshly criticized Medvedev and his mentor and predecessor Putin for saying that they will decide between them who should run for president in Russia's March 2012 presidential vote. He described the statements as a show of conceit and disrespect for Russian voters.
Both leaders have ignored the criticism. Putin, who was president from 2000 to 2008, has deplored the collapse of the Soviet Union as the "greatest geopolitical catastrophe of the 20th century."
Still, Putin congratulated Gorbachev in a telegram Wednesday, praising him as "one of the great statesmen of modern times, who have made a significant impact on the course of world history." Putin also hailed Gorbachev's charity activities.
Gorbachev is celebrating his birthday with family and friends in Moscow on Wednesday. On March 30, he plans to attend a charitable gala concert in London's Royal Albert Hall to help raise money for treating patients with blood cancer, the disease that killed his wife Raisa in 1999.