Imam Zeqirja Qazimi was handed down a ten-year sentence, the court said in a statement.
His six associates were convicted for trying to gather recruits and for fighting for the IS there from 2012 to 2014. They got jail terms ranging from three to eight years.
"They have intentionally called on other persons to commit or participate in terrorist acts, participate in the activities of a terrorist group and try to gather funds and material resources for it."
Local media reported that Qazimi was responsible for recruiting 11 fighters in Kosovo who joined the IS. Three of them were killed in Syria, media reported.
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The men were arrested in August and were detained at a high-security prison.
As the verdict was being handed down, the court was sealed off by anti-terrorist police wearing helmets and bulletproof jackets.
Muslim-majority Kosovo is home to 1.8 million people, around 300 of whom have joined the jihadists' frontlines in Iraq and Syria in recent years -- the highest ratio in any European country.
They say around 50 homegrown jihadists have been killed in fighting while around 120 have returned to Kosovo.