After being named the winner Saturday night, Stjernberg, 22, who was a competitor on the reality singing competition show "Idol," took the stage at Stockholm's Friends Arena for an encore performance, The Local.se reported.
"Thank you!" he shouted out while singing his hit "You."
"It's unbelievable, how the hell did this happen?" Stjernberg said after the show. "I'm going to take Eurovision home this year. This has been the best night of my life."
Stjernberg's win came after a five-week extravaganza qualifying rounds that consisted of 32 different acts performing in five sold-out shows across the country. More than three million people viewed the shows at home.
Stjernberg will go on to perform in the Eurovision contest to compete against top performers from other European countries.
Eurovision is set to take place in May in Malmo, Sweden.