At the age of 16, despite being a U.S. citizen, he signed a contract with the Nationals on July 2, 2016, as an international free agent out of the Dominican Republic.

[5] García advanced quickly in the 2018 season, earning a midseason promotion from the Single-A Hagerstown Suns to the High-A Potomac Nationals, and he was the youngest player and the first ever born in the 2000s selected to the All-Star Futures Game in 2018, playing for Team World against fellow Nationals infield prospect Carter Kieboom and Team USA.

[6] García was the youngest player invited to participate in a major league spring training camp in 2019, with the Nationals.

[8] On August 14, 2020, García's contract was selected to the major leagues and he made his debut that day against the Baltimore Orioles, filling in for the injured Starlin Castro.

He became the Nationals everyday second baseman, following the trades of infielders Josh Harrison and Trea Turner as well as the suspension and subsequent release of Starlin Castro.

In doing so, García became the third player in Nationals/Expos history with six hits in a single game, joining Anthony Rendon (2017) and Rondell White (1995).