Ronaldo, who has found the net 140 times in the competition, was given the prize ahead of the inaugural League Phase draw in Monaco.
After receiving the award from UEFA president Aleksander Ceferin, Ronaldo said: 'For me it's a pleasure to be here. This award means a lot to me. The Champions League is the highest in football, the records speak for itself but to play in that competition is special. It's great to be here, I have nice memories when I come to Monaco for this gala.
Although Ronaldo is no longer playing in the Champions League as he is at Al-Nassr in Saudi Arabia, he has fond memories of the competition.
'Our life is memories and I have very good ones. Let's see what the future brings. We always mention the first one, it's the most special. I remember when I was in Manchester, I scored in the final, missed a penalty and it was so special.'
Ronaldo, who scored 140 Champions League goals, won the competition five times
As he alluded to, Ronaldo won the Champions League with Manchester United in 2008 as the Red Devils defeated Chelsea on penalties in the final.
He won the competition on four occasions with Real Madrid - in 2013-14, 2015-16, 2016-17 and 2017-18.
Ronaldo also played in the Champions League for Juventus.
Lionel Messi, who has enjoyed a rivalry with Ronaldo throughout his career, is the second highest scorer in Champions League history with 129 goals.
Barcelona striker Robert Lewandowski is in third place with 94 goals.