He started his career off in Demark with Rosenhoj before moving to Brondby. Agger made his Brondby debut at the age of 19 in a league match against OB Odense.

• 他在丹麦罗森荷队开始职业生涯，随后加入布隆德比。19岁时，他首次代表布隆德比出场，在联赛中对阵奥登斯队。