The Portugal star shed tears after helping his team win the UEFA Nations League at the Allianz Arena in Munich on Sunday.
Ronaldo scored to help his side draw level with Spain 2-2 in the final, then watched as his teammates won the penalty shootout 5-3.
"I have many titles with my clubs, but nothing is better than winning for Portugal," he said.
"These are tears. It's mission accomplished and so much joy."
The 40-year-old had been the first to run out onto the field for the pre-game warm-up, sparking a huge roar from supporters.
Three days after helping Portugal to their first win over Germany for 25 years, scoring the winner for a 2-1 victory in the Nations League semi-finals, Ronaldo conceded that he won't be able to play forever.
On Sunday he was driving the team again, though it was initially a frustrating game as his chances were limited by Spain's hard-working defenders.
Nuno Mendes fired Portugal level after Martin Zubimendi opened the scoring. Then Mikel Oyarzabal put Spain ahead 2-1 at the break.
But Ronaldo was in the right place at the right time to fire home the equaliser in the 61st minute, setting off joyous scenes among his faithful fans. It was Ronaldo's 138th international goal. Nobody has ever scored more for their country.
Ronaldo kept trying in what was his record-extending 221st appearance for the country, but eventually had to go off in the 88th to standing ovations from fans and a hug from coach Roberto Martinez.
"I had already felt it during the warm-up, I had been feeling it for some time, but for the national team, if I had to break my leg, I would have broken it," Ronaldo said.
"It's for a trophy, I had to play and I gave it my all."
Ronaldo's future is uncertain as his contract with Saudi club Al-Nassr only runs to the end of June.
That didn't stop him celebrating Portugal's second Nations League triumph, having won the inaugural tournament in 2019.
"We are small in size but we are big in talent, big in personality," Manchester United's Portuguese captain Bruno Fernandes said.
"We knew it would be a very difficult game. Spain are one of the best national teams in the world. But we also have a very good team. When we have this togetherness it is very difficult to beat us."
Earlier on Sunday in Stuttgart, Kylian Mbappe scored one and set up the other as France beat Germany 2-0 for third place.
Aurelien Tchouameni set up club teammate Mbappe to score just before the break after the hosts had dominated the first half.
The Real Madrid superstar then set up substitute Michael Olise to seal the result in the 84th minute after a much-improved second-half performance from the visitors.
With PA & DPA.
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