Philadelphia Phillies
Coming out of high school, McGarry was selected in the 31st round by the Texas Rangers in the 2017 Major League Baseball draft, but opted not to sign with the team.[10] As a senior at Virginia, McGarry was selected by the Philadelphia Phillies in the fifth round of the 2021 Major League Baseball draft and this time chose to turn pro.[11]
McGarry began his professional career with the Low-A Clearwater Threshers. He was promoted to the High-A Jersey Shore BlueClaws and finished the season with 1–0 record with one save and a 2.96 ERA and 43 strikeouts in 24+1⁄3 innings pitched.[12] After reaching Triple-A for the first time with the Lehigh Valley IronPigs the following year, entering the 2023 season, McGarry was ranked by MLB Pipeline as the Phillies' third-best prospect.[13] However, McGarry struggled and spent much of the year back at the Class-AA level with the Reading Fightin' Phils. He pitched to a 6.00 ERA across three levels while issuing 50 walks in 60 innings pitched. Ahead of the 2024 season, the Phillies announced McGarry would move out of the starting rotation into a full-time relief role.[14]
As a reliever, McGarry's command issues were amplified. He walked 10.23 batters per nine innings and was ultimately transitioned back into a starting role in the Arizona Fall League after the 2024 season. Coming off a strong showing with the Glendale Desert Dogs, McGarry returned to Lehigh Valley's rotation in 2025 with a drastically reduced walk rate.[15]
Despite McGarry's improved results, the Phillies opted not to add him to the 40-man roster ahead of the Rule 5 draft, leaving him exposed. On December 10, 2025, McGarry was selected by the Washington Nationals with the third overall pick in the Rule 5 draft.[16] He was designated for assignment by the Nationals on March 22, 2026.[17] On March 24, McGarry was returned to the Phillies organization.[18] He made five appearances for Triple-A Lehigh Valley, but struggled to a 9.00 ERA with four strikeouts over four innings of work.