Bernard Mendy was born on 20 August 1981 in Évreux, in the Normandy region of France, and is of Senegalese descent. He began his professional career with SM Caen in the 1998–99 season before fulfilling a childhood ambition by joining Paris Saint-Germain in 2000, the club he had supported from a young age.
A right-back known for his blistering pace and consistent overlapping runs, Mendy spent the bulk of his playing days at PSG, where his eight-year stint was interrupted only by a season-long loan at Bolton Wanderers. During his time in Paris he collected two Coupe de France medals (2003–04 and 2005–06) and a Coupe de la Ligue winner's medal in 2007–08, the latter secured when he came off the bench and calmly converted the decisive penalty in a 2–1 final victory over RC Lens. He also earned a call-up to the French senior national team, making his debut in a match against Brazil.
In 2008 Mendy moved to newly promoted Hull City on a three-year deal, where he memorably scored a lob against Manchester United in a 4–3 defeat. Later spells took him to Danish side Odense Boldklub, Stade Brestois, and Indian clubs Chennaiyin FC — with whom he won the inaugural Indian Super League title in 2015 — and East Bengal FC, before he retired at the end of the 2016 ISL season.
After hanging up his boots, Mendy moved into coaching, serving as assistant manager at Paris Saint-Germain Féminine from December 2017 and briefly acting as caretaker manager when he guided the side to a Coupe de France féminine victory over Lyon.