[1] He starred in a production of The Secret Diary of Adrian Mole[2] and was cast by Austrian filmmaker, Michael Haneke for the TV movie, The Traitor and the 1997 films The Castle and Funny Games.
[3] Giering's portrayal of the psychopathic killer Peter in Funny Games was considered a breakout performance.
His best known roles were in Sebastian Schipper's Absolute Giganten (1999) as Floyd, and in the film Baader (2002), portraying the leader of the Red Army Faction.
Since 2006, Giering starred in the ZDF series Der Kriminalist as the Commissioner Henry Weber.
[6] Giering had publicly discussed his struggles with alcoholism and emotional issues.