The full-back, who can play on either defensive flank, marked his Foxes debut with a goal in a 4-0 Carabao Cup Second Round victory away at his former club, Luton Town, in September 2019. He also played in Leicester’s third round victory, a 3-1 away triumph at Burton Albion the following month. In December 2019, the defender made his Premier League debut in City’s 2-0 defeat of Watford at King Power Stadium.
Early on in his time at the Club, when Justin featured, Leicester often won, with his league debut followed by victories over Aston Villa (twice) and West Ham United, as well as FA Cup wins against Wigan Athletic and Brentford.
In 2020/21, meanwhile, Justin became an invaluable figure for the Foxes, making 31 appearances in all competitions, including six outings in the UEFA Europa League, until an ACL injury cruelly cut short a promising season for the former England Under-21s international.
He made a long-awaited return early in 2022 and later signed a new four-and-a-half year deal at the Football Club. He would make 19 outings for the Foxes in the second half of the 2021/22 campaign, in the Premier League, UEFA Europa Conference League and the Emirates FA Cup.
Born in Luton, Justin joined his previous club, Luton Town, in 2005 and progressed through the club’s youth system. He made his senior debut during a 4-1 victory over Exeter in May 2016, and went on to feature 39 times for the Hatters in all competitions the following season.
The young defender scored his first Luton goal in April 2017, in a 4-1 win over Accrington Stanley and was named his hometown club's Young Player of the Season for 2016/17.
During the 2017/18 campaign, Justin made 22 appearances in all competitions for the Hatters, scoring twice and helping them to promotion from Sky Bet League 2. Luton achieved a second successive promotion at the end of the 2018/19 season, winning the League 1 title, in what was the defender’s most influential season to date.
Justin featured for Graeme Jones’ side 52 times in all competitions, 43 of those outings coming in the league, scoring three goals and again picking up the Young Player of the Season award. The defender received his first call-up to the England Under-20s squad in August 2017 and made his maiden appearance in a 3-0 win against the Netherlands that same month.
His full debut came four days later, in a 0-0 draw with Switzerland. Two years later, in September 2019, Justin was called up to the Under-21s squad and made his bow in a 2-0 win over Kosovo, coming on as a substitute in the UEFA European Qualification fixture.
He eventually made eight appearances for the Young Lions. In the summer of 2022, a reward for his talents and his determined recovery from serious injury arrived in the form of a first-ever call-up to Gareth Southgate's England squad ahead of four UEFA Nations League fixtures in June. He made his debut, from the start, in a UEFA Nations League group stage clash away at Hungary.
Following relegation in 2023, Justin's ability and experience continues to be a useful tool for Enzo Maresca as the Foxes bid for promotion from the Sky Bet Championship.