Hahn, 50, has spent virtually his entire professional career in politics. He was LA's elected city attorney before defeating mayoral hopeful Antonio Villaraigosa in a run-off election last month.

Hahn is considered a more moderate Democrat than Villaraigosa. While Villaraigosa was able to secure the backing of unions that represent many clerical workers at City Hall, Hahn was able to capture the support of most Police and Firefighter unions—as well as most of the building industry trades.

Both Hahn and Villaraigosa also received large contributions from local developers. Some slow-growth advocates now worry that Hahn might become too "pro-development" in order to reward the construction trade unions and builders who financially supported his successful campaign.