After the 2017 season, Baseball America rated Giménez as the Mets' best prospect.[4] He spent the 2018 season with both the St. Lucie Mets and the Binghamton Rumble Ponies, batting .281/.347/.409 with six home runs, 46 RBIs, and 38 stolen bases in 122 total games between the two clubs.[5] That summer, he played in the 2018 All-Star Futures Game.[6] He returned to Binghamton for the 2019 season,[7] hitting .250/.309/.387 with nine home runs, 37 RBIs, and 28 stolen bases over 117 games.
The Mets added Giménez to their 40-man roster following the 2019 season.[8] Giménez made the Mets' Opening Day roster in 2020,[9] and made his Major League debut on July 24, 2020, at Citi Field as an eighth inning defensive replacement for Robinson Canó at second base.[10] On July 29, Giménez made his first start, and recorded his first career hit off of Boston Red Sox pitcher Nathan Eovaldi, a single, in the second inning. In the sixth inning of the same game, Giménez tripled off Marcus Walden to record his first career RBI.[11]
In 2022 with the renamed Guardians, Giménez experienced a breakout season, batting .297 with 17 home runs and 69 RBI. He was elected to the All Star Game at 2nd base and started as a replacement for the injured Jose Altuve. His reputation as a clutch hitter developed in 2022, as he had a 281 WRC+ in high leverage situations, meaning he nearly tripled the average hitter's production in that position.[18] Giménez won a Gold Glove Award for his performance at second base.[19] He was also selected for the second team on the 2022 All-MLB Team.[20]
Prior to the 2023 season, Giménez represented the Venezuelan national baseball team in the 2023 World Baseball Classic.[21] On March 30, Giménez signed a seven-year major league contract with the Guardians worth $106.5 million. The deal includes a club option for the 2030 season.[22] On April 12, 2023, a relay throw to home plate by Giménez struck the head of umpire Larry Vanover, who was hospitalized with non-life threatening injuries.[23] In 2023 he batted .251/.314/.399, had the lowest average exit velocity of all AL batters (84.8 mph), and led the AL in percentage of balls that were softly hit (21.7%).[24][25]