Since his debut in 2016, the young defender has played 93 games and scored one goal. He has seven titles: he has raised the Argentine Cup three times, won the Super Cup and the Libertadores against Boca and added two Cups.  Montiel is a key member of the River Plate team and is a member of the senior Argentina national squad with two appearances.
In March 2019, Montiel was named in Argentina’s squad for friendlies against Venezuela and Morocco by manager Lionel Scaloni. On 22 March, Montiel made his debut against Venezuela.