Coulson, who went on to become director of communications for David Cameron, was given the sentence by Mr Justice Saunders at The Old Bailey on Friday morning.
The judge said hacking at the News of the World had caused "serious distress to the subjects" and referred to the newspaper’s delay in telling police about voicemails on murdered school girl Milly Dowler’s phone as "unforgivable".
News of the World chief reporter Neville Thurlbeck and ex-news editor Greg Miskiw were also both jailed for six months.
Glenn Mulcaire, a former private investigator, was given a six-month suspended sentence and 200 hours of community service while the former News of the World reporter James Weatherup was given a four-month suspended sentence.
Coulson is also set for a retrial over the seperate charge of alleged payments to public officials.