After finishing school in 1977 at Wandsbeker Matthias-Claudius-Gymnasium, Freytag first completed an apprenticeship as a bank clerk and then studied law at the University of Hamburg.

For some time he worked in overseas offices of the Federal Republic of Germany in Chicago and at the German Business Association of Hong Kong.

On 15 September 2007 he was elected as the successor of Dirk Fischer to become chairman of the CDU in Hamburg with 93.62% of the votes.

On 17 March 2004 he was appointed as the Senator for Urban Development and Environment of Hamburg in the state government led by Ole von Beust and on January 1, 2007, he succeeded Wolfgang Peiner as Finance Senator of Hamburg following Peiner's resignation from political office.

In March 2010, Freytag resigned from his position as chairman and as Senator of Finance to instead become CEO of the Schufa Holding AG.