Gallego was loaned from Boston River to NorthEast United for the 2018–19 Indian Super League season.
[2] Gallego won the Fans' Player of the Month award for October in an online poll conducted by the league.
[3] On 21 September 2020, Gallego signed a contract extension, keeping him at NorthEast United until the end of the 2020–21 season.
Gallego won the Hero of the Month award for January in an online poll conducted by the league.
On 29 September 2021, NorthEast United and Gallego have agreed a one-year contract extension for the upcoming season.