Early years and Tours Mercadal began his managerial career as an assistant at his final playing club,
Gap FC, before being their head coach between 2005 and 2008 in the fourth-tier
Championnat de France Amateur. For the next four years he was assistant at
Amiens SC in
Ligue 2 and the
Championnat National; he was interim manager on 23 October 2009 in a 1–0 loss at
ES Troyes AC. Known for his passion, he vomited after defeat in his early career. In June 2012, Mercadal was hired at fourth-tier
USL Dunkerque, winning promotion in his first season. After coming 5th, 6th and 6th in the third tier, he was appointed at
Tours FC in Ligue 2 in June 2016. He drew 0–0 at home to Ajaccio on his professional career debut on 29 July, and was dismissed on 18 February 2017 with his team in last.
Paris FC Mercadal found another job in Ligue 2 in June 2017, being hired by
Paris FC, who had been restored to the division after the administrative relegation of
SC Bastia. He came 8th in his one season at the
Stade Charléty, and was eliminated from the eighth round of the
Coupe de France 3–2 at third-tier
Entente SSG.
Caen On 8 June 2018, Mercadal was announced as the manager of
Ligue 1 side
Stade Malherbe Caen on a three-year deal, with Paris FC being compensated for the last year of his contract. His top-flight debut on 12 August was a 3–0 loss at reigning champions
Paris Saint-Germain FC. His team reached the quarter-finals of the Coupe de France via a 7–5 win at Bastia on 5 February 2019. He left by mutual consent on 25 May, after a 1–0 home loss to
FC Girondins de Bordeaux on the final day and relegation to Ligue 2.
Cercle Brugge and Ligue 2 return In July 2019, Mercadal was hired in the first foreign job of his career, at
Cercle Brugge K.S.V. in the
Belgian First Division A. He was fired on 7 October after losing nine of ten league games and losing 1–0 at home to fourth-tier
R.U.S. Rebecquoise in the sixth round of the
Belgian Cup. On 16 May 2020, Mercadal returned to Dunkerque on a two-year contract, with the team newly promoted to Ligue 2. Having avoided the relegation play-off on goal difference in his one season back at the
Stade Marcel-Tribut, he left by mutual consent. Mercadal returned to work in Ligue 2 on 4 January 2022 at
Quevilly-Rouen, signing an 18-month deal at the 11th-placed club. In May he received a four-match ban, of which two were suspended, for an obscene gesture on his return to Caen. He left for personal reasons at the end of the month. ==Managerial statistics==