After a lower-league playing career, he began managing at Vannes in 2002, winning the Championnat National in 2008 and finishing runners-up in the Coupe de la Ligue in 2009.
Le Mignan spent his entire playing career in the French lower leagues with Montagnarde, Pontivy, Locminé and Vannes.
[18] In June 2018, Le Mignan had the first foreign experience of his career, being chosen as assistant for a year at Al-Gharafa SC in the Qatar Stars League, under fellow Breton Christian Gourcuff.
[22] Le Mignan took on his former club Vannes on 29 October 2022 in the seventh round of the Coupe de France, losing on penalties.
[23] The following 26 May, with a 2–1 final day win at Orléans, the team won the league title ahead of Dunkerque to play in Ligue 2 for the first time in their history.