After a trial that spanned almost eight months, Mr. Coulson was found guilty last week on a charge of conspiring to intercept phone messages. Five other defendants who, like Mr. Coulson, had denied the charges were acquitted. They included Rebekah Brooks, the former chief executive of Mr. Murdoch’s British newspaper subsidiary and Mr. Coulson’s onetime lover.
Reporters in the courtroom on Friday said Mr. Coulson displayed no emotion when the sentence was read out. If he is given time off for good behavior, he could be paroled after serving half of his sentence. Standing alongside him in the courtroom were four other people involved in the hacking scandal who had admitted their part in the scandal earlier in the trial and who were sentenced to up to six months.
Mr. Coulson, who edited Mr. Murdoch’s tabloid The News of the World from 2003 to 2007, and the newspaper’s former royals editor, Clive Goodman, also face a retrial on separate charges of making illegal payments to police officers in return for two royal telephone directories. Prosecutors called for the retrial after the jury failed to reach a verdict on those charges.
The phone hacking scandal in Britain goes back more than a decade, when a private investigator hired by The News of the World hacked the voice mail of Milly Dowler, a teenager who had been abducted and was later found murdered, in 2002. When news of that episode broke in July 2011, a wave of public revulsion forced Mr. Murdoch to close the newspaper.
Mr. Coulson, 46, had faced a maximum sentence of two years.
“Mr. Coulson has to take the major shame for the blame of phone hacking at The News of the World,” Judge John Saunders said. “He knew about it, he encouraged it when he should have stopped it.”
While Mr. Coulson’s lawyer said no one in the news business realized that phone hacking was illegal at the time of the offenses, Judge Saunders said on Friday: “I do not accept ignorance of the law provides any mitigation. The laws of protection are given to the rich, famous and powerful as to all.”
During the trial, prosecutors listed more than 1,900 occasions on which journalists commissioned a private investigator, Glenn Mulcaire, to hack into voice mail messages.
A prosecutor, Andrew Edis, said the list of victims read like a “Who’s Who of Britain in the first five years of the century.”
On Friday, Mr. Mulcaire, who had carried out much of the hacking, including in the case of Milly Dowler, received a suspended prison sentence of six months. Like Mr. Goodman, the former royals editor, Mr. Mulcaire served a prison term in 2007 after a conviction for intercepting voice mail messages on the mobile phones of politicians, film stars and royal aides, including some left by Prince William. His lawyer had argued that he should not be punished twice.
Two former News of the World senior journalists, Greg Miskiw and Neville Thurlbeck, were jailed on Friday for six months each, while their former colleague James Weatherup received a four-month suspended term.
Mr. Coulson’s time as editor of The News of the World came to an end in early 2007, when he resigned over the earlier hacking case that sent Mr. Mulcaire and Mr. Goodman to prison.
Mr. Cameron, then in opposition, subsequently hired him as communications director — a post he maintained after the election of 2010 that brought Mr. Cameron to power.
As the scandal began to resurface in 2011, Mr. Coulson resigned again — this time from his position at 10 Downing Street. Mr. Cameron has faced accusations that he showed a lack of judgment in hiring him and keeping him on.
The opposition Labour Party has accused Mr. Cameron of seeking to curry favor with Mr. Murdoch by hiring Mr. Coulson, hoping to win the electoral endorsement of the Murdoch newspapers. Michael Dugher, a Labour spokesman and lawmaker, declared on Friday that “this a damning verdict for David Cameron as well as Andy Coulson.”
“Now, not only is trust in the prime minister’s judgment deeply damaged, his government is tainted,” Mr. Dugher said.
Asked about his former aide’s sentence, Mr. Cameron said on Friday that it was “right that justice should be done and no one is above the law, which is what I have always said.”
The scandal inspired an array of investigations by Parliament, by the police and by a senior judge, Lord Justice Sir Brian Leveson, whose inquiry concluded in November 2012 with a call for tighter press regulation.