Romero's first professional club were Acassuso of Primera B Metropolitana, making thirty-two appearances in his debut season while scoring four times; including his first against Colegiales.
[1] On 10 January 2016, Romero completed a permanent transfer to fellow Primera División side Argentinos Juniors.
[1] On 16 January 2021, Romero scored a hat-trick as Defensa y Justicia defeated Coquimbo Unido in the Copa Sudamericana semi-finals; taking his tally in the competition for the club to nine goals in eight games.
[1] He then netted in the final against Lanús on 23 January, with Defensa defeating their domestic rivals to win their first Sudamericana title; the centre-forward finished as the top scorer with ten goals.
[1] On 7 July 2021, River Plate signed Romero on a three-and-a-half-year contract to replace the recently transferred Rafael Santos Borré.