He won the run - off primary election on September 29 , defeating Green , 62 percent to 38 percent .
On September 15 , 2009 , de Blasio came in first in the Democratic primary , garnering 33 percent of the vote .
de Blasio won the run - off primary election on September 29 , defeating Green , 62 percent to 38 percent .
On September 15 , 2009 , de Blasio came in first in the Democratic primary , garnering 33 percent of the vote .