Born in Madrid, Mel started his career with Real Madrid, joining the club’s youth system in 1974 at the age of 11 and playing alongside the likes of Emilio Butragueño and Míchel, although he never represented the first team, only competing at senior level with the reserves. In late 1987, after a very brief spell with CA Osasuna (he did not make his official debut), he moved to Segunda División with CD Castellón where he played two years, helping the Valencian Community side return to La Liga in his second season after an absence of seven years.

Mel enjoyed his best years at Real Betis, signing with the Andalusia team in 1989 and helping them achieve promotion in his debut campaign whilst winning the Pichichi Trophy with 22 goals, one better than in the previous season at Castellón. In the following year he played his first and only season in the top level, scoring 14 times but once again suffering immediate relegation; his debut in the competition was on 2 September 1990, and he found the net in a 2–2 home draw against Sporting de Gijón.

Mel started coaching one year after retiring, his first club being amateurs CD Coslada in the Community of Madrid. In 2001, after one year at Real Murcia in division two, he replaced Valencia CF-bound Rafael Benítez at the helm of CD Tenerife, having his first spell in the top flight as a coach and suffering relegation.

On 15 February 2010, after a string of poor results, Mel was sacked by Rayo, being replaced by director of football Felipe Miñambres who helped the club to the 11th place. In the summer he signed with former side Betis also in the second tier, leading the Verdiblancos back to the top division in his first year.

Mel coached Betis to the seventh position in the 2012–13 campaign, with the subsequent qualification to the UEFA Europa League. He was relieved of his duties on 2 December 2013, however, after falling to a 0–4 derby loss at Sevilla FC and conceding a last-minute 2–2 home equaliser to Rayo Vallecano.

On 9 January 2014, Mel signed an 18-month contract with West Bromwich Albion of the Premier League. His first match in charge came 11 days later, a 1–1 home draw against Everton.

Mel obtained his first win in English football after seven games, with a 2–1 success at Swansea City on 15 March 2014. On 12 May 2014, one day after the end of the season where he led the Baggies to the 17th place, he left by mutual consent with a record of three wins from 17 games.

Mel returned to former club Betis in December 2014, with a contract lasting until the end of the campaign. He was the April 2015 Segunda División Manager of the Month after his team won all their games, scoring 11 goals and conceding two. On 24 May, after only one loss in his tenure, the league was won as champions and promotion achieved with a 3–0 win over AD Alcorcón.

Mel was sacked on 11 January 2016, with his team in 15th place following a poor run of form and also strained relationship.

On 28 February 2017, Mel was appointed at Deportivo de La Coruña until the end of the season, replacing the sacked Gaizka Garitano at a team two points above the relegation zone in the top division and winless in the new year. He was himself fired on 24 October, due to poor results.

Mel was named manager of UD Las Palmas on 4 March 2019, replacing Paco Herrera who had been sacked earlier the same day. He signed a contract until the end of the season.