Bruno was born in Rocourt, a local town in the city ofLiège, to Italian parents. As a result, he possesses dual-nationality. He began his career playing for hometown club FC Liège where his father was a coach. After seven yearsat the club, after Liège endured financial difficulties, Bruno moved to one of the biggest clubs in the countryStandard Liège. He spent seven years at Standard and was a two-time national champion at under-12 and under-17 level with the club. Towards the end of his tenure at Standard, Bruno featured with the club's reserve team in a match against Anderlecht. Despite receiving a professional contract offer from Standard, Bruno departed the club to join Lille in France. He justified departing the club citing France's better training methods and Lille's close proximity to his home in Belgium.
Lille
Bruno began his career at Lille in the club's youth academy in Luchin. After two years in the club's academy, during the 2008–09 season, he began playing on the club's reserve team in the Championnat de France amateur, the fourth level of French football. Bruno was promoted to the reserve team full-time in the following season. He appeared in 27 matches scoring a team-high 11 goals. After playing the 2010–11 season with the reserve team, on 8 June 2011, Bruno signed his first professional contract agreeing to a one-year deal with Lille. He was, subsequently, promoted to the senior team by manager Rudi Garcia and assigned the number 19 shirt. Bruno made his professional debut on 11 January 2012 appearing as a substitute in a 2–1 defeat to Lyon in the Coupe de la Ligue. Fours days later, he made his league debut appearing as a substitute in another defeat, this time to Marseille. Bruno was sent on loan to Bastia for the 2013–14 season.
On 3 July 2017, Cercle Brugge announced the transfer of Gianni to the organization. He signed a contract for one season.
International career
Bruno is a Belgian youth international and has played for all levels for which he has been eligible. In total with the Belgian youth international teams, he has attained 59 caps and scored 33 goals.
