Hainaut was born on 18 February 2002 in
Boulogne-sur-Mer, France. He is a native of
Sainte-Catherine, France. In 2010, Hainaut joined the youth academy of French side
Lens at the age of seven. He started his senior career with French side
US Boulogne. On 6 August 2021, he debuted for the club during a 1–1 draw with
Chambly. On 13 August 2021, he scored his first goal for the club during a 3–1 win over
Red Star. He made thirty league appearances and scored one goal while playing for the club. He also played for their reserve team. In 2022, he signed for Italian side
Parma. On 17 September 2022, he debuted for the club during a 3–1 win over
Ascoli. He helped the club win the
Serie B league. On 16 August 2025, Hainaut signed a three-season contract with
Venezia in
Serie B. ==References==