Scott 'Scooter' Braun was arrested in November 2009 following an event at the Roosevelt Field Mall in Long Island, New York, after fans caused a stampede at the venue resulting in one girl being hospitalised.
Police claimed that Braun had been aware that the crowd was becoming unruly, but had refused to send out a Twitter message cancelling the event.
However, charges against Braun have now been dropped after Bieber agreed to make a public-service announcement for an anti-cyberbullying campaign.
"Mr Braun created a dangerous safety situation using Twitter," District Attorney Kathleen Rice said in a statement, reported by E! Online. "This is a unique opportunity to use the internet, social media and Justin Bieber's star power to help make our communities safer."
Bieber has publicly supported his manager following the arrest, insisting that Braun always has both Bieber and the fans' safety in mind.
In addition to the public service announcement, Bieber's label Island Def Jam have agreed to reimburse the county the $8,000 it cost for the law enforcement response.