"When we are very good, we're the best of the best. Congratulations Salvador Sobral," President Marcelo Rebelo de Sousa wrote in a message to the 27-year-old crooner.
A cheering crowd thronged Lisbon airport to welcome him and his older sister Luisa Sobral, who wrote the winning song. They were escorted through the crowd by police.
"Salvador! Salvador! Portugal!Portugal!" they yelled as the triumphant singer shyly waved to them, holding a bouquet of roses in one hand.
"This prize is going to trigger a certain madness about me but I know it is short-lived," he said at a brief press conference. "What interests me is making music with meaning."
Fans meanwhile showered praise.
"It was a well deserved win, with a song that was different from all the others," said Pedro Antunes, a 29-year-old musician who follows the contest every year.
Maria Amorim, 49, held up a poster proclaiming: "Salvador, you have fulfilled my childhood dream" that Portugal would one day win the contest.
"A page of history has been written in Portuguese this evening at Eurovision. Bravo Salvador! Bravo Portugal," Prime Minister Antonio Costa tweeted.
