Kohli, who tops the global batting rankings, said that the Portuguese goalscorer remains a superstar even at the age of 34.
"For me, Cristiano is above everyone else. His commitment and work ethic is unmatched. He wants it that bad - you can see it every game," Kohli told the FIFA website.
"In my opinion he has taken on more challenges and succeeded at all of them. He's the most complete player I have seen and his work ethic, as I mentioned, is unmatched.
"He inspires people. I don't think many people do that. He's also a leader and I love that. Absolutely love it. He has amazing belief too."
Ronaldo and Kohli have both built up huge international fan bases. Ronaldo has more than 177 million followers on Instagram while India's cricket captain has more than 30 million on Twitter.
Kohli is also a keen football follower and co-owner of Indian Super League football team, FC Goa.
The cricket superstar said he hopes his country can soon reach a World Cup finals, despite their current FIFA ranking of 103.
"With new talent coming in to make the difference, and our skipper Sunil Chhetri leading the team with amazing composure and inspiration, I see us qualifying very soon for the World Cup," said Kohli.