Nicolas Julio Nkoulou Ndoubena (born 27 March 1990) is a Cameroonian former professional footballer who played as a centre-back.
Nkoulou began his career in the French league with Monaco, where he spent three years before signing for Marseille in 2011. With Marseille, he won his first senior trophy, the Coupe de la Ligue in the 2011–12 season. In 2016, he left Marseille for Lyon, but after a disappointing year he left to join Italian club Torino, initially on loan but later on a permanent basis. Though initially impressing, he fell out of favour, and left the club in 2021, and signed for English club Watford that same year.
Internationally, Nkoulou played 75 times for Cameroon between 2008 and 2017, and decided to retire shortly after winning the 2017 Africa Cup of Nations, scoring the equalising goal in the final. He represented Cameroon in three World Cups and three Africa Cup of Nations. In September 2022, he was called up to the national team for the first time after 5 years. He then acquired eight more appearances for his country until 2023.
Nkoulou began his career at Kadji Sports Academy in Douala, the same academy that produced the likes of Samuel Eto'o, Carlos Kameni, and Eric Djemba-Djemba. In late 2007, it was announced that he was acquired by the principality-based side AS Monaco. He agreed to a three-year professional contract with the club. He spent the latter portion of the 2007–08 season playing with Monaco's CFA squad, before joining the squad for preseason in July 2008, where he was handed the number 3 kit.
Nkoulou made two appearances during the pre-season starting their opening friendly match against fellow Ligue 1 side Toulouse and also starting against Croatian side NK Zagreb. He made his professional debut on 13 September 2008 in a 2–0 victory over Lorient starting the match before being substituted in the 65th minute. Though he made 24 appearances in the 2008–09 season,
The 2009–10 season saw Nkoulou to play as defensive midfielder for most of the season under the new management of Guy Lacombe and new signing, Sébastien Puygrenier. As the 2009–10 season progressed, Nkoulou signed a new contract with the club, keeping him until 2012 and was then reverted to central defence. NKoulou also played in the Coupe de France Final, coming on as a substitute for Eduardo Costa in the 111th minute, in a 1–0 loss against PSG and went on to make 23 appearances in the 2009–10 season despite being committed to the African Cup of Nation.
In the 2010–11 season, Nkoulou found himself in the transfer speculation and ended up staying at the club despite fallen out with Lacombe. Nkoulou continued remain in the first team, playing in the defensive midfielder position for most of the season and central defence. Despite suffering from injuries and suspension, Nkoulou finished the 2010–11 season, making 30 appearances. However, following their relegation to Ligue 2, Nkoulou was among key players to be expected to leave the club.
His performances with Monaco have led to him being scouted by several prominent European clubs. English club Arsenal, Spanish sides Sevilla and Atlético Madrid and French champions Olympique Lyonnais have all declared their interests in the Cameroonian defender. During his time at AS Monaco, Nkoulou made 78 appearances and has started every match since playing the full 90 minutes in them all. He has yet to score a goal.
On 29 June 2011, Nkoulou passed his medical and signed for four years with Marseille for €3.5 million. Marseille and Lyon found themselves competing over their interest signing Nkoulou before he chose Marseille.
After missing two matches, due to suspension he received while at Monaco, Nkoulou made his Marseille debut on 14 August 2011, in a 2–2 draw against Auxerre. In the next match against Saint Étienne on 21 August 2011, Nkoulou was involved in an incident with Florent Sinama Pongolle. But following the reviewing by the Disciplinary Committee of the LFP, he was received a three match ban. While serving his suspension in the league, he made his Champions League debut on Matchday 1 of the Group–stage, helping a club kept a clean sheet, in a 1–0 win against Olympiacos on 13 September 2011 and went on to play ten Champions League Matches. Eight days later on 21 September 2011, Nkolou made his return to the first team, in a 2–0 win over Evian. His performance throughout October saw him earned the club's player of the month of October. Nkolou continued to remain in the first team for the 2011–12 season despite another suspension (which he got a two match ban against Dijon) and a knee injury. Despite this, Nkoulou helped the club win against Lyon 1–0 in the final of Coupe de la Ligue, winning the cup for their first piece of silverware since 1981, as well as, being named Man of the Match. After finishing the 2011–12 appearance, making 46 appearances in all competition, Nkoulou was named Trophées UNFP du football's Team of the Year of 2012 and was nominated for the Prix Marc-Vivien Foé Award, but finished as runner–up to Younès Belhanda. Nevertheless, Nkoulou was awarded 2011–12 Olympique de Marseille Player of the Season.
In the 2012–13 season saw Nkoulou found himself in the transfer speculation when the club began to suffer financial trouble, but stayed at the club and insisting on honouring his contract. Nkoulou was ever–present in the 2012–13 season, having played all the match in the league and scored his first goal for the club, in a 2–1 win against Troyes on 3 March 2013. During the season, Nkoulou suffered a knee ligament injury and was sidelined for weeks, but managed to return to the league. At the end of the 2012–13 season, Nkoulou was named Trophées UNFP du football's Team of the Year of 2013 for the second time running.
Prior to the 2013–14 season, Nkoulou stated he was prepared to leave Marseille in the summer, prompting attracted interests from his former club Monaco, who were just promoted back to Ligue 1, and Arsenal. After the club set a higher price tag on him, Nkoulou remained at the club and started a bad start when he conceded a goal, in a 3–1 win over Guingamp in the opening game of the season. Despite this, Nkoulou redeemed himself soon after to continuously remain in the first team under the new management of Élie Baup. On 4 January 2014, Nkoulou extended his contract with Marseille, keeping him until 2016. As the 2013–14 season progressed, Nkoulou suffered a knee injury, which kept him sidelined for one match. After making his return, Nkoulou went on to score two goals later in the season against Saint Étienne and Sochaux. Nkoulou made 46 appearances and scoring twice in all competitions in the 2013–14 season.
Ahead of the 2014–15 season, the club were keen on selling Nkoulou, but following a friendly match against Bari, it appeared hinted that he wanted to stay at the club. His good performance against Guingamp on 23 August 2014 earned him Team of the Week on Matchday 3. Then on 19 October 2014, Nkoulou scored his first goal of the season, in a 2–0 win over Toulouse. Two weeks later, on 2 November 2014, Nkoulou scored again, in a 2–1 win over Lens. However, as the 2014–15 season, his appearance was soon restricted to 26 appearances in competition, due to injuries and international commitment with Cameroon. After two months without playing, Nkoulou made his first team return on 12 April 2015, in a 1–0 loss against Bordeaux and went on to help the finished the season in the 4th place at two points of a qualification in the Champions League.
Ahead of the 2015–16 season, Nkoulou's contract set to expire and haven't renewed his contract, though his future remained undecided. In the 2015–16 season, Nkoulou made his first appearance of the season, having missed through opening game of the season, in a 1–0 loss against Reims on 16 August 2015. In a match against Lille on 29 January 2016, Nkoulou captained Marseille for the first time following Steve Mandanda's absence, which they drew 1–1. In a match against Saint-Étienne on 21 February 2016, Nkoulou received a straight red card in a 1–1 draw. In addition to his disciplinary issues, Nkoulou was suspended three times in every Coupe de France matches, Nkoulou started in the Coupe de France Final, which they lost 4–2 against PSG. At the end of the 2015–16 season, the club faced a difficult season with three different managers during the season and finished the league in thirteenth place and finished the season, making 41 appearances in all competition.