The 46-year-old, who went on to become director of communications for British Prime Minister David Cameron, was found guilty last week at the Old Bailey, the Central Criminal Court of England and Wales.
Coulson was one of four ex-journalists at the British tabloid to be sentenced, along with private investigator Glenn Mulcaire.
Five defendants, including former News International chief Rebekah Brooks, were cleared of all charges last week.
Sentencing the five men, Mr Justice Saunders said it was not his role to pass judgement on the relationship between the police, press and the government. This had been the job of the Leveson Inquiry, he said.
What was relevant, he said, was the amount of hacking and the period over which it occurred.
Hacking had picked up “intensely personal” messages, the judge said, causing “serious distress to the subjects”.
He referred to the hacking of murdered schoolgirl Milly Dowler’s phone, saying the News of the World’s delay in telling police about voicemails had been “unforgiveable” reported BBC.