Real Madrid forward Ronaldo was carried off on a stretcher in tears in the 25th minute, eight minutes after injuring his knee in a clash with France’s Dimitri Payet.
France, the firm favourites, were unable to capitalise on Ronaldo’s absence, although they almost won it at the end of normal time when substitute Andre-Pierre Gignac turned and hit the inside of the post.
Raphael Guerreiro hit the bar with a free-kick for Portugal after 108 minutes, but seconds later they were ahead when Eder fired a low, 25-yard drive past keeper Hugo Lloris.
Ronaldo, who had given his Portugal team-mates animated encouragement in the break before extra time, was offering as much tactical advice as coach Fernando Santos in chaotic closing moments – and he was reduced to tears once more at the final whistle before lifting the trophy that has eluded his country for so long
The underdogs had their day in the Euro 2016 final as Portugal overcame hosts France in Paris.
Fernando Santos’ side sneaked out of their group with three draws and rode their luck in Sunday’s final before snatching a victory in dramatic fashion in the second half of extra time.
Inside a buzzing Stade de France, their task was made all the more difficult when star man Cristiano Ronaldo was forced off in the first half , but Portugal dug deep to keep the hosts out despite huge pressure.
Raphael Guerreiro struck the post with a gorgeous free-kick in the additional 30 minutes but Swansea reject Eder was the hero for A Seleccao, rifling home to seal a memorable win against the odds.
Eder is the hero
What an unlikely hero for Portugal – and Swansea fans will be more shocked about it than the rest of us.
Eder signed for the Swans for £5m last summer. He left in January after 13 goalless Premier League appearances.
But in the biggest game of his career, he wrote his name into Portuguese folklore.
During the second-half of extra time, the striker cut inside from the left before unleashing a fierce drive into the bottom corner beyond Lloris.
It was his first competitive goal for his country!
It send the Portugal fans inside the stadium wild and in turn devastated a whole nation.
Heartbreak for Ronaldo but happy ending arrives
He was always going to leave a lasting impression on this one but the way Cristiano Ronaldo bowed out after just 24 minutes was quite devastating.
Portugal’s talisman was left in serious discomfort after a heavy clash with Dimitri Payet, that ultimately ended his Euros dream.
His reluctance to come off even saw him try and return to the field but after pulling up again, it was obvious his night was over.