When they were relegated from the Premier League in 2019, Kongolo remained for the first half of the 2019–20 season, before joining Fulham on loan in January 2020, making the deal permanent in October 2020.

[7] A year later, he was promoted to the first team ahead of the 2011–12 season[8][9] and appeared on the substitute bench, around the same time playing for the reserve side.

[11] In the 2012–13 season, Kongolo then made his first league start on 24 August 2012 against Heracles Almelo following the injury of Stefan de Vrij and the suspension of both Joris Mathijsen and Bruno Martins Indi, where he played the whole game, in a 2–1 win.

Despite suffering a minor hip injury against Go Ahead Eagles on 30 March 2014,[22] Kongolo finished the 2013–14 season, making eighteen appearances in all competitions.

[28] From that moment on, Kongolo regained his first team place, mostly playing in the centre-back position, partnering with Sven van Beek, for most of the season.

[32] Kongolo established himself in the first team as the left-back position and started the season well when he set up one of the goals, in a 2–0 win over Vitesse on 23 September 2015.

[44] After returning to the first team,[45] Kongolo captained the club the first time in his professional career in the quarter-final of the KNVB Cup against Vitesse, which saw them lose 2–0.

[47] However, in a 1–0 loss against Sparta Rotterdam, on 5 March 2017, Kongolo suffered a thigh injury in the first half and was substituted as result.

[citation needed] After much speculation regarding his future at Feyenoord, Kongolo signed a five-year contract with reigning Ligue 1 champions Monaco, for an undisclosed transfer fee, reported to be in the region of €12 million.

[54][55] He was handed the traditional number 4 central defender shirt upon his arrival, most recently worn by Fábio Coentrão in the 2015–16 season.

[54] After being kept out of the squad for multiple fixtures, Kongolo eventually made his Monaco debut 13 October, in a 3–2 defeat to Lyon in the domestic competition.

[69] During the off-season, Kongolo was linked with a return to the Premier League, with Watford and divisional newcomers Aston Villa expressing their interests in signing the defender.

[71] Kongolo was named on the Fulham bench as an unused substitute in their goalless draw against Charlton Athletic, before making his debut in a 4–0 FA Cup defeat to Manchester City on 26 January 2020.

[75] After his future at Huddersfield Town continued to remain in doubt, Kongolo returned to Fulham, now in the Premier League after achieving promotion during Kongolo's loan spell during the second half of the previous league campaign; he joined them on a permanent deal on 16 October 2020, the domestic transfer deadline day, for an undisclosed fee, believed to be around £4 million, potentially rising to £7 million.

[90] The following year, on 14 October 2014, Kongolo scored his first Netherlands U21 in the qualification round of UEFA European Under-21 Championship, in a 5–4 loss against Portugal U21.

[91] Kongolo's performances for Feyenoord saw him included in senior team manager Louis Van Gaal's squad for the 2014 FIFA World Cup in Brazil.

[94] Nevertheless, Kongolo was included in the twenty-three man squad in the tournament, where he made one appearance in their final group game after entering as a substitute for Dirk Kuyt in the 89th minute against Chile; the Dutch won 2–0.

[97] Upon signing for Huddersfield Town in January 2018, manager David Wagner expressed his pleasure and excitement in the player joining the club, stating, "Terence has qualities that will really suit our style of play.