Fernando Santos' team claimed a first major international honour for their country when substitute Eder fired a superb extra-time winner to stun an expectant Stade de France.
Their hopes appeared to suffer a terminal blow early in the match when Ronaldo suffered a knee injury in a challenge with France midfielder Dimitri Payet.
The Real Madrid superstar twice attempted to play through the pain after receiving treatment but admitted defeat in his personal battle after 25 minutes.
Nevertheless, Ronaldo dried his tears and sought to focus his colleagues on the task at hand during the interval, before spending the rest of the match as a notably animated figure on the touchline.
"It was a very, very tough moment. It was a really tough moment for me and for the team," Cedric said of Ronaldo's injury. "I think everybody was a little bit in shock but at half-time Cristiano had fantastic words with us.
"He gave us a lot of confidence and he said, 'Listen people, I'm sure we will win this Euro so stay together and fight for it'.
"It was unbelievable. All the team had a fantastic attitude and showed that when you fight as one you are much much stronger.
"He was fantastic. His attitude was unbelievable. At half-time he helped a lot, our colleagues, he had always a lot of motivational words. All the team reacted to them so it was very, very good."
Portugal survived some near misses after the interval as tournament top scorer Antoine Griezmann headed a glorious 65th-minute chance over before Andre-Pierre Gignac struck the post during stoppage time.
Ronaldo's replacement Ricardo Quaresma drew strength from French profligacy and Portugal appeared the more dangerous side in extra time before Eder's emphatic breakthrough.
"When I saw them missing one, two, three chances, it only made me believe even more that if we had an opportunity, we could win the game," Quaresma said.
"In the end, we worked hard and we achieved it. We are very happy.
"We knew that working hard all together, we would have a good chance. It's a moment of pride, a moment of joy because we have written our names down in history."