Darwin Gabriel Núñez Ribeiro was born in Artigas, Uruguay, to an impoverished family. His father, Bibiano Núñez, was a builder, and his mother, Silvia Ribeiro, was a hawker of milk bottles.

At the age of 17, Núñez joined Montevideo-based Uruguayan club Peñarol, marking the beginning of his professional football career.

Núñez made his professional debut with Peñarol in the Uruguayan Primera División, coming on as a second-half substitute in a 2–1 away loss against River Plate Montevideo.

Núñez signed with Spanish Segunda División club Almería on a five-year contract for a rumored club record fee of US$4.5 million plus $1.5 million in variables.

Núñez signed a five-year contract with Portuguese club Benfica for a club record fee of €24 million, becoming the most expensive signing in Portuguese football history.

In his second season with Benfica, Núñez won the Bola de Prata for top scorer in the Primeira Liga with 26 goals in 28 games, being named in the Primeira Liga Team of the Year and Primeira Liga Player of the Year.

Núñez signed with Premier League club Liverpool for a transfer worth €75 million (£64 million), marking a significant step in his career.

Núñez had a promising first season at Liverpool, scoring crucial goals and establishing himself as a key player for the club.

Núñez played a crucial role in Liverpool's EFL Cup campaign, providing assists and scoring goals, including a brace against Bournemouth. He was praised as one of Liverpool's best performers throughout the campaign.

Núñez continued to excel at Liverpool, scoring important goals and providing assists, including a brace in stoppage time to win against Brentford.