Two Canadian high schoolers — Josh Naylor and Michael Soroka — went in the first round on Monday night while college left-hander Jeff Degano was chosen in the second round.
Naylor, a first baseman from Mississauga, Ont., became the highest Canadian position player ever drafted when the Miami Marlins selected him 12th overall.
"The moment that I heard my name was a moment that I'll never forget," Naylor said in a statement. "I'm just happy that the Marlins picked me and that I got to live the experience with my family."
Soroka, a right-handed pitcher from Calgary, went 28th to the Atlanta Braves while Degano, from Surrey, B.C., was picked by the New York Yankees 57th overall out of Indiana State.
It was the best showing by Canadians on the first day of the draft since 2007 when Phillippe Aumont (11th), Kyle Lotzkar (53rd) and Trystan Magnuson (56th) were among the top 60 players selected.
Naylor, a six-foot, 225-pound left-handed hitter, has been a standout on the junior national team for the past few years. He participated in last year's MLB junior home run derby at Target Field, finishing second behind American Luken Baker.
Toronto Blue Jays prospect Dalton Pompey, also of Mississauga, tweeted out a congratulatory message to Naylor moments after the selection was announced.
"That's huge! Making Mississauga and Canada proud! All the best," Pompey wrote.
The Blue Jays took right-handed pitcher Jon Harris out of Missouri State with the 29th pick, and chose high school right-hander Brady Singer of Florida with their second-round selection.
Toronto drafted Harris in the 33rd round out of high school in 2012, but he chose to go to college rather than sign with the Blue Jays then.
"(2012) was one of those years where I was six-foot, 160 pounds coming out of high school — I knew I wasn't that high quality a guy like I was this year," Harris said on a conference call from St. Louis. "It was a tough decision but I felt like Missouri State was the place for me in order to get better and get to where I am now today — the 29th overall pick and Toronto again."
Brian Parker, the Blue Jays director of amateur scouting, described Harris as a "guy with weapons to get outs," highlighting his curveball and a slider which he called Harris' "best secondary pitch."
"It's our kind of guy, an athletic kid with a big arm and a breaking ball," Parker said. "We talked to him tonight, he's a great kid and the makeup is good. We're looking forward to getting him going."
The Arizona Diamondbacks selected Vanderbilt shortstop Dansby Swanson with the No. 1 pick, setting off a history-making run at the position.
With the second pick, Houston took LSU's Alex Bregman — marking the first time the first two players chosen were shortstops since Shawon Dunston (Cubs) and Augie Schmidt (Blue Jays) got drafted in 1982. Colorado made it 3 for 3 by taking Florida high schooler Brendan Rodgers at No. 3 overall.
A fourth shortstop went 10th, with Philadelphia selecting Georgia high schooler Cornelius Randolph.
Swanson seamlessly switched from second base to shortstop this season as a junior. He was the Most Outstanding Player at the College World Series last year, helping the Commodores to the national championship. Swanson is a finalist for the Golden Spikes Award and Howser Trophy, given to college baseball's top player.
"An exceptional baseball player that has all of the intangibles and makeup of a championship-type player for which this organization is building a foundation on," Diamondbacks scouting director Deric Ladnier said in a statement.
It was the 50th anniversary of the first draft in 1965, and the first for new Commissioner Rob Manfred, who took over when Bud Selig retired in January.
"I actually was going to call him on the way out here and I got tied up," Manfred said, minutes before stepping to the podium to begin announcing the first-round selections. "So I didn't get any advice. I think I can get through it."
The Astros received the No. 2 pick as compensation for not signing pitcher Brady Aiken, last year's top pick. Aiken was taken by Cleveland at No. 17 despite having Tommy John surgery in March.
Houston kept things in the family at No. 5, taking Florida high school outfielder Kyle Tucker, the younger brother of Astros outfielder Preston Tucker. He broke his brother's school record with 31 career homers, and has the power to potentially move to a corner outfield spot at the next level.
UC Santa Barbara fireballing right-hander Dillon Tate was selected by Texas with the fourth pick, giving the Rangers a potential staff ace or late-inning reliever. He was one of the best closers in the country last year, and established himself as an outstanding starter this season for the Gauchos.
At No. 6, Minnesota drafted Illinois closer Tyler Jay, a lefty who could be used as a starter at the next level because of his excellent command of four pitches.
Arkansas slugging outfielder Andrew Benintendi went seventh to Boston; Vanderbilt righty Carson Fulmer was the No. 8 pick by the Chicago White Sox; and the Chicago Cubs selected Cincinnati outfielder Ian Happ ninth overall.
— With files from The Associated Press