Sunu was born in
Châteauroux, Indre. He began his career at the
LB Châteauroux academy, but moved to
Arsenal in July 2007 on a four-year contract for a fee between £700,000 and £1 million. At Arsenal whilst playing for the club's academy, Sunu won the
FA Youth Cup of
2009 beating
Liverpool by 6–2 on aggregate in both legs of the final. He was also victorious in winning the
Premier Academy League of
2009 thus helping the club towards an historic youth double.
Arsenal 2009–10 season Gilles had an impressive first half of the season with
Arsenal Reserves, making nine appearances and scoring four goals. He made his
first team debut for the club when he started a
League Cup match against
West Bromwich Albion on 22 September 2009, playing 58 minutes before being substituted for
Carlos Vela. On 9 December 2009, Sunu made his
UEFA Champions League debut in Arsenal's 1–0 away defeat to
Olympiacos, coming on for
Jack Wilshere on 76 minutes.
Loan to Derby County On 18 February 2010, Sunu signed for
Derby County on loan until the end of the
2009–10 season. He made his debut for the Rams as a first-half substitute in a 1–0 defeat to
Swansea City, coming on for the injured
Kris Commons before being later substituted on the 85-minute. Sunu scored his first goal in a 4–1 defeat away to
Reading on 10 March 2010. After
Stephen Pearson and
Rob Hulse worked a smart one-two on the left side of the area and when Pearson was halted by a challenge, Sunu poked the loose ball past goalkeeper
Adam Federici from the edge of the area. In total, Sunu made nine appearances for Derby before returning to Arsenal slightly earlier than intended after picking up an injury in Derby's penultimate game of the season away to
Bristol City.
2010–11 season After scoring in the final of the
2010 UEFA European Under-19 Football Championship in July, Gilles suffered a cartilage injury in his right knee that would keep him out of action for two months. Sunu made his comeback for the Arsenal Reserves against Blackpool at the end of September and went on to make eight appearances, scoring twice.
Lorient On 31 January 2011, Sunu opted to join
Lorient on loan for the remainder of the
2010–11 campaign. He made his debut for
Les Merlus as a second-half substitute in the 2–0 victory over
Caen. Gilles created his first assist in the 3–2 away victory to
Lens. After rounding Lens goalkeeper
Vedran Runje, Sunu flicked the ball back from the byline for
Kevin Gameiro to head in from five yards to make the score 2–2. Gilles completed his loan at Lorient making nine appearances, all from the substitutes' bench.
Sky Sports reported that Lorient manager
Christian Gourcuff was keen to re-sign Sunu as well as his Arsenal teammate
Francis Coquelin on an additional year's loan, with Sunu hinting that he would welcome a return to the seaport town. in 2013 Gilles Sunu signed a four-year contract with Lorient on 31 August 2011, just three days after being an unused substitute in Arsenal's heavy 8–2 defeat to
Manchester United. Sunu made his full debut for Lorient in the 1–1 away draw against
Sochaux, coming on as a 62nd-minute substitute for
Arnold Mvuemba. On 6 November 2011, Sunu scored his first goal for Lorient and made an assist in the 2–0 home win against
Ajaccio. Sunu went past his man and cut the ball back for
Yann Jouffre to score from outside the box. Before Jouffre turned provider and played Sunu in on goal with only the keeper to beat. Sunu scored his second goal of the season in the quarter-finals of the
Coupe de la Ligue of 2012 in the 1–0 away victory to
Le Mans. Gilles beat Le Mans goalkeeper
Giorgi Makaridze at the near post on the 70th minute after coming on as a 62nd-minute substitute for
Innocent Emeghara.
Évian Sunu moved in January 2015 to the
Parc des Sports so as to join up with that of
Évian in a one-and-a-half-year deal. He in all played 10 matches for Les Roses, scoring three goals altogether. ==International career==