Oliver Dulic, Serbia's minister of environment and urban development in the previous Democratic Party-led government, was found guilty of having favoured a company when issuing licences for an optical cable network.
Two of his aides were sentenced, to terms of one and three years, the Tanjug news agency reported, quoting the verdict of Serbia's special court for organised crime.
Dulic has denied the accusations and claimed that the case is politically motivated.
Since his nationalist Serbian Progressive Party came in power in 2012, Vucic has pledged to root out high-level corruption, which is believed to be widespread in Serbia.
Several ministers and top officials from the Democratic Party-led government from 2008 to 2012 were arrested soon after the new administration took charge, but Dulic is the first to be sentenced.
All three defendants said they would appeal to the verdict, Tanjug reported.