Dahlin, who plays for Frolunda HC in the Swedish league and was widely expected to be the first pick, follows Mats Sundin, who was the top choice of the Quebec Nordiques in 1989.
“I just want everything to start,” Dahlin said. “I'm going to bring everything I have to that city. I'm super excited. I can't wait.”
Russian forward Andrei Svechnikov went second to the Carolina Hurricanes and the Montreal Canadiens used the third pick to get Finnish centre Jesperi Kotkaniemi.
The draft had a decided Europe flavour as four of the top six players were Europeans. The first American was Brady Tkachuk who went to the Ottawa Senators at No. 4 and the Phoenix Coyotes took the first Canadian Barrett Hayton with the fifth pick.
The 18-year-old Dahlin said he was happy to call Buffalo home despite the fact they haven't had a winning season in the past seven seasons and have missed the playoffs eight years in a row.
“It's amazing to finally put on the Buffalo Sabres' jersey,” Dahlin said. “I've been there twice. I love that city.”
The six-foot-three, 185-pound Dahlin was honoured as the best defenceman at the 2018 world junior championship in Buffalo, registering six assists in seven games. He also played twice for Sweden as a 17-year-old at the 2018 Pyeongchang Winter Olympics.
At number six, the Detroit Red Wings chose the brash Halifax Mooseheads winger Filip Zadina who vowed to make teams that passed on him pay down the road.
“I'm telling my agent if they will pass on me, I will fill their net with the puck,” the Czech Zadina said. “Yeah, it's just I want to prove to them that they have done a bad decision.”
The lone trade of the day came before the draft when the Colorado Avalanche acquired backup goalie Philipp Grubauer and defenceman Brooks Orpik from the Stanley Cup champion Washington Capitals for the 47th pick. The Capitals were willing to get rid of Orpik and Grubauer so they could create salary cap space to sign free agents.