[4] Hardy signed with the Detroit Tigers in April 2013, and they assigned him to the Erie SeaWolves of the Class AA Eastern League.

Hardy finished with a 2–2 record and a 1.63 earned run average (ERA) as a reliever before he was promoted to the Toledo Mud Hens of the Class AAA International League.

[5] Hardy was a non-roster invitee to spring training in 2014, and impressed as he competed for a role as the team's long reliever.

[8] Hardy made his major league debut for the Detroit Tigers the next day in a game against the Kansas City Royals, pitching two scoreless innings, allowing one hit, walking two and striking out two.

Hardy made the Tiger roster for Opening Day in the 2015 season, but was held back for extended spring training due to a minor injury.

[14] Hardy made his first major league start on May 13, giving up two earned runs in 4+1⁄3 innings against the Seattle Mariners, while throwing a career-high 79 pitches.

[15] In his third start on May 27, Hardy went a career-high seven innings and threw 85 pitches, giving up just one run and three hits against the Chicago White Sox to earn his first major league win as a starter.

Due to injuries to Francisco Liriano and Jordan Zimmermann, Hardy continued to pitch in the Tigers starting rotation through the month of June.

[17] Back in the rotation on August 3, Hardy took a no-hitter against the Oakland Athletics into the seventh inning, before an infield single by Jed Lowrie ruined the no-hit bid.

[21] After putting up a 4.47 ERA in 44 1/3 innings in 2019, mostly with elbow pain, Hardy was optioned to the Toledo Mud Hens on August 9.

Hardy opted to receive PRP injections to treat his elbow on August 13 after seeking a second opinion during the 72-hour window to report to Toledo.

[27] On January 28, 2021, Hardy signed a minor league contract with the Milwaukee Brewers organization and was invited to Spring Training.

On February 27, 2023, Hardy was announced as the head baseball coach at Central Lakes College in Brainerd, Minnesota.