McCarthy was a fifth-round pick of the Tampa Bay Rays out of the University of Virginia in 2015. After several seasons in the Rays organization, including time with the 2017 Triple-A National Champion Durham Bulls, he was traded to San Francisco in July 2019. McCarthy appeared in 474 games in the Minors over six seasons and made his Major League debut for the Giants in 2020.
McCarthy played for Sacramento in Triple-A West in 2021 and spent the 2022 season with the Orix Buffaloes of Nippon Professional Baseball in Japan.