Harvey attended Bandys High School in Catawba, North Carolina. The Baltimore Orioles selected him in the first round of the 2013 Major League Baseball draft. He signed with the Orioles on June 20, 2013, and made his professional debut that season for the Gulf Coast Orioles of the Rookie-levelGulf Coast League. In August he was promoted to the Aberdeen IronBirds of the Class A-Short SeasonNew York-Penn League. Overall, he started eight games, pitching to a 0–1 win–loss record with a 1.78 earned run average with 33 strikeouts in innings pitched. Prior to the 2014 season, Harvey was ranked by Baseball Prospectus as the 58th-best prospect in baseball. He spent the season with the Delmarva Shorebirds of the Class ASouth Atlantic League where he pitched to a 7-5 record and 3.18 ERA in 17 starts. On May 12, 2015, Harvey was shut down for six weeks due to tightness in his elbow. He did not pitch for a minor league team in 2015. Harvey threw in an instructional league in September 2015. He began the 2016 season on the disabled list and then underwent Tommy John surgery in July which ended his season. In 2017, Harvey pitched for Aberdeen and Delmarva, along with three rehab games with the Gulf Coast Orioles, pitching to an 0-1 record and 0.96 ERA with 30 strikeouts in total innings pitched between the three teams. The Orioles added Harvey to their 40-man roster after the 2017 season. They assigned him to the Bowie Baysox of the Class AAEastern League to begin the 2018 season, but promoted him to the major leagues on April 9, to provide a fresh player for the relief corps. However, he did not make his major league debut and was optioned back to Bowie two days later, and spent the remainder of the year there. In nine starts, he compiled a 1-2 record with a 5.57 ERA. On August 17, 2019, Harvey was promoted to the major leagues. He made his major league debut that night versus the Boston Red Sox, striking out two batters over one scoreless inning. He was credited with his first major-league win in a 4-1 victory over the Kansas City Royals in his Camden Yards debut three nights later on August 20. After he kept the game tied at 1-1 by retiring all three batters he faced in his only inning of work, Hanser Alberto's three run homer in the bottom of the eighth gave the Orioles its eventual winning margin.
