Andreas Christensen was born on 10 April 1996 in Lillerød, Denmark, and spent around eight years in the Brøndby youth system before Chelsea won the race for his signature. He chose Chelsea, he has said, because of the style of football the club played. After making his professional debut in a League Cup tie against Shrewsbury Town in October 2014, he was sent on a two-season loan to Borussia Mönchengladbach in 2015, where he became a regular starter and scored twice against Werder Bremen in a single Bundesliga match.
Returning to Chelsea for the 2017–18 season, he established himself in the first team and was named the club's Young Player of the Season. A composed, reading-the-game centre-back who is comfortable in possession, he went on to win the UEFA Champions League with Chelsea in 2021, coming on as a substitute in the final against Manchester City after Thiago Silva was injured. He also collected FA Cup, UEFA Europa League, UEFA Super Cup, and FIFA Club World Cup winners' medals during his time at Stamford Bridge.
Christensen made his Denmark senior debut in June 2015 and has represented his country at two FIFA World Cups (2018, 2022), scoring in the group-stage match against France at the 2022 tournament. He was named Danish Footballer of the Year in 2023.
In July 2022 he joined FC Barcelona on a five-year contract, and has since added La Liga, Copa del Rey, and Supercopa de España titles to his collection. Chelsea still list him as part of their history; his current club is Barcelona.