Dendoncker transferred from K.S.V. Roeselare to R.S.C. Anderlecht in 2009, choosing that club ahead of Standard Liège, Club Brugge and K.R.C. Genk. After performances for the youth team in the NextGen Series and a training camp in Turkey, he was incorporated into the first team in January 2013. He models his game on that of the Spanish midfielder Sergio Busquets. He made his professional debut on 21 July in the 2013 Belgian Super Cup, replacing Dennis Praet for the final nine minutes of the 1–0 win over Genk at the Constant Vanden Stock Stadium. On 26 September, he extended his contract until 2016. However, it was not until 1 August 2014 that he debuted in the Belgian Pro League, on the first day of the season away to KV Oostende. After scoring his first professional goal on 18 January 2015 in a 3–0 win at Lierse S.K., Dendoncker was praised by former Anderlecht player Paul Van Himst, who said that there was no better player at his position in the club. He played six matches in the 2014–15 Belgian Cup, which his team lost 2–1 in the final to Brugge. Anderlecht won the 2016–17 Belgian First Division A. Dendoncker scored five goals along the way, including two on 18 December in a 4–0 home win over K.A.S. Eupen. He also played all 16 games in their European campaign that season, which ended with elimination by eventual winners Manchester United in the quarter-finals of the UEFA Europa League. In the first leg of that tie on 13 April 2017, he scored a late equaliser in a 1–1 draw.
Wolverhampton Wanderers
On 9 August 2018 Dendoncker moved to newly promoted English Premier League club Wolverhampton Wanderers on an initial season-long loan with an obligation on Wolves to make the player a permanent Wolves signing in summer 2019. He made his debut on 28 August in the second round of the EFL Cup away to Sheffield Wednesday, with coach Nuno Espírito Santo making nine changes from the previous game. In late September, The Football Association rejected the obligatory purchase clause in Dendoncker's Wolves contract and made his deal became permanent for €15 million. He finally made a league appearance on 5 December in a 2–1 win against Chelsea, playing the final nine minutes in place of goalscorer Raúl Jiménez, and scored his first Premier League goal on his sixth appearance in the competition, in a 1–3 win at Everton on 2 February 2019. Dendoncker committed a foul in the Wolves penalty area with just 180 seconds remaining of Wolves's April 2019 FA Cup semi-final with Watford at a time when Wolves were leading the tie 2–1 and thereby conceded the penalty that enabled Watford to draw the game at the end of normal time. Watford went on to win the fixture 3–2 in extra time, thus preventing Wolves from reaching what would have been the club's first FA Cup final since 1960. Dendoncker's second Premier League goal gave Wolves a crucial 1–0 home win over Fulham on 4 May 2019 that put Wolves in pole position to finish the season in seventh place in the league and thus in line to secure Europa League qualification in the event of a victory for Manchester City over Watford in the forthcoming FA Cup final on 18 May 2019. Dendoncker became a permanent Wolves signing on 1 July 2019, his original loan agreement having included an obligation on the club to sign him permanently at the end of the original season-long loan period. Following the introduction of Video Assistant Referees by the Premier League for the 2019–20 season, he was the first Wolves player to have a 'goal' ruled out using VAR in a league match during Wolves' opening fixture away to Leicester City on 11 August.
International career
Dendoncker was first called up for the Belgium national football team on 22 May 2015 by manager Marc Wilmots, along with his Anderlecht teammate Youri Tielemans. He made his debut on 7 June in a friendly game away to France, replacing Jason Denayer for the final five minutes of a 4–3 win. On 4 June 2018, manager Roberto Martínez named Dendoncker in Belgium's 23-man squad for the 2018 FIFA World Cup in Russia. He made his tournament debut on 29 June in a 1–0 win over England at the Kaliningrad Stadium, with both teams fielding unfamiliar teams having already advanced to the last 16.
Personal life
Dendoncker was born in Passendale, West Flanders to pig farming parents. He is the middle of three footballing sons: in May 2017, his elder brother Andres was playing for Roeselare and his younger brother Lars had been given his first professional contract aged 16 at Brugge. Dendoncker moved to Brussels to play for Anderlecht while in their under-15 team and suffered from homesickness while adjusting to the difference between a largely white rural setting and a diverse urban environment. He attended the Sint-Guido-Instituut school in Anderlecht at the time that it was being filmed for the fly-on-the-wall documentary De School van Lukaku focusing on his teammate Romelu Lukaku. He has noted that he speaks in West Flemish to his family, but the Brabantian dialect when doing interviews for Anderlecht.
