An uncompromising figure at the back, Agger initially struggled to make his name at Liverpool because of injuries, but established himself ahead of Jamie Carragher during the 2011/12 season and is now a fixture for his club and country.
Beginning his career at Brondby, Agger rose through the ranks and had an almost immediate impact when he helped his side to the Danish league title in his first full season in the side. He was subsequently named Denmark's Players' Player of the Year and made his bow for the national team as he earned his first full cap for Denmark in June 2005 against Finland.
He sealed a £5.8 million move to Liverpool in January 2006 - making him the most expensive export in Denmark's history - but was unable to force his way regularly into the first team. Knee and foot injuries hindered his progress, before a back injury almost ended his career. However, he fought back to fitness and was able to play a crucial role in the final two games of Denmark's 2010 World Cup qualifiers.
He made four appearances during the qualifying for Euro 2012, including victories over Iceland, Cyprus and Norway.
Strengths: Strong, powerful and committed in the tackle, he has a good reading of the game and positions himself well to make interceptions. Has a rocket of a left-foot shot too.
Weaknesses: For a man of his size, he is not dominating in the air, has a short fuse when he is not playing regularly and has suffered a host of injury concerns.
Career high: Winning the Danish Superliga 2004-05 championship with some superb performances for Brondby and sealing his move to Liverpool in January 2006.
Career low: A back injury made him think about retiring before the start of the 2009-10 season. "I asked myself if it was worth continuing playing. When you can't even lift your own child out of bed, then something is terribly wrong," he said.
Style: Powerful, quick, uncompromising, a committed defender.
Quotes: "You always get frustrated when you pick up these injuries and you can't play but all you can do is try to use it as a positive - I set myself a target and I worked hard towards it, on the pitch and in the gym." Daniel Agger, October 2009.
Trivia: Agger is a tattoo artist and has a number of tattoos on his body including a Viking on his upper right arm with the quote 'Memento mori' ('Remember you will die'); although he didn't do it himself.