Born and raised in the suburbs of Phoenix, Arizona, Liberatore was selected by the Tampa Bay Rays in the first round of the 2018 Major League Baseball draft out of high school.

[3] As a senior at Mountain Ridge in 2018, he posted an 8–1 win–loss record with a 0.93 earned run average (ERA) with 104 strikeouts in 60+1⁄3 innings[4] and was named Arizona's Gatorade Baseball Player of the Year.

Liberatore began the 2019 season in extended spring training before he was assigned to the Bowling Green Hot Rods of the Class A Midwest League on May 15,[9] with whom he spent the remainder of the year.

[13] In late May, he was placed on the temporarily inactive list while he competed for a spot on the United States national baseball team, in advance of the 2020 Summer Olympics.

[15] Team USA qualified for the Olympics, but Liberatore was ultimately not named to the roster in part due to the Cardinals' lack of organizational depth.

[21][22] He made his MLB debut on May 21 as the starting pitcher versus the Pittsburgh Pirates, throwing 4+2⁄3 innings and giving up seven hits, four earned runs, and two walks while striking out three.