A jury at London's Old Bailey court, after four days of deliberations, cleared Neil Wallis, 64, of conspiracy to hack phones while he was working alongside former editor Andy Coulson, who was jailed for hacking last year.
Wallis was not accused of hacking phones, but prosecutors alleged he "knew" it was happening and "agreed" to it.
He accused Scotland Yard and the Crown Prosecution Service (CPS) of a "vicious politically driven campaign" against the press.
At that time he was editor Coulson's right-hand-man, who has been previously found guilty and prosecuted for his role in hacking phones at the erstwhile Sunday weekly.
Also Read
Wallis is the last of the journalists from the 'News of the World' to face legal action over the hacking the tabloid used in the hunt for exclusive stories.
In total eight of the tabloid's reporters have been convicted of illegally accessing voicemails, including Coulson, a former director of communications for Prime Minister David Cameron.
"All the evidence has been aired publicly in a court of law and the jury have made their decision. That is a decision we respect.