Friedrich has emerged as a regular at right-back for Germany, having impressed for Hertha Berlin. He joined Hertha in the summer of 2002 from Arminia Bielefeld and has become a regular on the right flank, although he can also play in the middle of defence. Solid in defence, his only limitation is his attacking play and his place could come under threat if coach Jurgen Klinsmann opts for a three or five-man defensive set-up. Made his national team debut in August 2002 in a 2-2 draw with Bulgaria and captained Germany in a friendly against Thailand two years later. Also wears the armband for the club side.