Harvey, an 18-year-old right-hander out of Bandys High School in Catawba, N.C., was selected with the 22nd overall pick. Hart, an outfielder from Parkview High School in Lilburn, Ga., was taken in the competitive balance round with the 37th overall pick.
"It's been exciting. A lot going on, but definitely one of the most exciting days of my life," Harvey said. "My brother told me the other day, 'Three years from now, you could be a junior in college or you could possibly be in the big leagues.' So I just want to start my professional career instead of going to school."
Harvey went 8-0 with 116 strikeouts in 11 games (eight starts) as a senior in 2013 after going 7-0 as a junior. He's the third consecutive right-hander taken by the Orioles in the first round, following Dylan Bundy and Kevin Gausman.
"He's got a very fast arm and, for an 18-year-old, advanced delivery mechanics. We think he has the potential to be a front-line starter down the road, and we're very happy to have him," scouting director Gary Rajsich said.
Hart batted .449/.560/.757 in 107 at-bats over 36 games in his senior season. He had 18 extra-base hits, 29 RBIs and 39 runs scored. He also stole 34 bases in 36 attempts. He led Parkview to state championships in 2011 and 2012.
"Josh is an exciting multitool player," Rajsich said. "We think he has the chance to hit at the top of the order. And when you can get a leadoff hitter with his kind of speed that can play center field, those guys are rare. They don't come around very often, so we're very excited to bring him into the organization."
Hart said during the news conference that he is "dying to meet" center fielder Adam Jones. Jones apparently heard about it, and left the clubhouse to meet Hart and Harvey before they even left the media room.
Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Twitter @britt_ghiroli. Derek Wetmore is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.