Christian Nørgaard was born in Copenhagen and grew up in Espergærde, Denmark. He came through the youth ranks at Lyngby before making his senior debut as a substitute in November 2011. A move to Bundesliga side Hamburger SV followed, though he failed to break into the first team and returned to Denmark in 2013, joining Brøndby IF.
It was at Brøndby that Nørgaard truly found his footing. He became a regular under manager Alexander Zorniger, was named the club's Player of the Year for 2017, and won the 2017–18 Danish Cup — the first silverware of his career. After 145 appearances and 11 goals, he moved to Fiorentina in 2018, but made only six Serie A appearances before leaving for English second-tier side Brentford in 2019.
At Brentford, Nørgaard became one of the club's most important players. He was part of the squad that won promotion to the Premier League in 2021 and was named both the Supporters' and Players' Player of the Year for the 2021–22 season, a campaign in which he attempted more tackles than any other Premier League player. He was appointed club captain in 2023 and went on to score a career-high six goals in his final season before signing for Arsenal in July 2025 for a reported £10 million.
A disciplined defensive midfielder with strong positional awareness and the ability to intercept play and pass forward quickly, Nørgaard is expected to add experience and solidity to Arsenal's midfield. He made his senior international debut for Denmark in September 2020 and has since represented the country at Euro 2020, the 2022 World Cup, and Euro 2024.