[2] Born in Tegucigalpa, Honduras, Núñez grew up in the United States, coming with his family on his father's investor visa in the early 1990s and graduating from W. T. White High School in Dallas, Texas.

[3][4] He was drafted by the Dallas Burn sixth overall in the 2004 MLS SuperDraft after one season of college soccer at Southern Methodist University for which he was named the Missouri Valley Conference freshman of the year.

He was renowned for his extraordinary vision and was instrumental in Los Leones's 2007/08 Clausura triumph, his performances also securing him the player of the season award.

[2] Núñez's excellent form with Olimpia and with the Honduras national football team led to him signing on loan for six months at Mexican Primera División side Puebla.

His performances on loan for Puebia earned Núñez a move to Cruz Azul for the 2009–2010 season, where he scored two goals in the CONCACAF Champions League.

After his 6-month contract ended, Núñez wanted to try his luck in Europe after turning down offers to join Mexican Premier League clubs.

After becoming a free agent, he left Olimpia to join Leeds initially on a trial basis before signing a permanent contract.

On 14 September, in order to gain match fitness, Núñez played 90 minutes in Leeds' 3–1 behind closed doors friendly win against Middlesbrough.

Leeds chose to exercise the option on Núñez's contract and the midfielder has extended his stay at Elland Road for another year.

[16] After playing five games for Honduras over the summer in the CONCACAF Gold Cup, Núñez was given extra time off before returning to Leeds for pre season training.

[29] Núñez scored his first goals for Leeds with a brace against Bradford City in the League Cup 3–2 win on 9 August.

[33] Núñez dropped to the bench in place of Andy Keogh against Manchester United, he came on as a second-half substitute and managed to miss one of Leeds' best scoring chances late on in the game.

[37] After being put on the transfer list by Leeds, Núñez was linked with a move to Yorkshire Rivals Doncaster Rovers and newly promoted Charlton Athletic.

[39] Núñez suffered a cruciate ligament injury on 3 September during Leeds United development squad's victory against Wigan.

Ramón made his second and third appearances in September after being called up by Reinaldo Rueda to play in the CONCACAF World Cup Qualifiers.

[46] On 23 January, Núñez played in the 2011 Copa Centroamericana final and helped Honduras win the tournament after beating Costa Rica 2–1.

[50] Nunez denied on his Twitter page that he had critisced the Honduras manager Luis Fernando Suárez after the 1–1 match against Guatemala in the Gold Cup.

[52] Núñez revealed in August 2011 he turned down a call up for Honduras to feature against Venezuela as it meant he would miss Leeds match against Bradford City.