The agency triumphed in the four-way pitch to secure the £4 million Tetra Pak account. It beat Clemmow Hornby Inge, McCann-Erickson and DFGW to the brief to turn Tetra Pak into a consumer brand while improving its image in the eyes of its business customers.
Separately, Royal Mail has confirmed the appointment of AMV and its sister Omnicom shops Proximity and Wolff Olins to handle its communications.
The above-the-line work is worth £20 million.
Last month, Royal Mail announced it had ruled out WPP, M&C Saatchi and Grey Worldwide from the pitch for its integrated account. Omnicom's presentation was the only one put forward for a second round of research. The results of this research led to the consortium's final appointment this week.
The incumbent, Bates UK, failed to make the shortlist when Royal Mail launched the review at the end of February.
Farah Ramzan, the managing director at AMV, said: "For Royal Mail, people make a difference. Its people have a pride in their business and we want to put that pride on display."
The Royal Mail relaunch campaign, designed to lift the brand after a slew of negative press and poor financial results, is expected to break in the autumn.
The ads will focus on Royal Mail's workforce, while highlighting Royal Mail's credibility as a business partner.
AMV Group's chairman, Michael Baulk, said: "Royal Mail has been the biggest pitch so far this year so it is very important for our group and our agency." He explained that integrated appointments in general tend to be "more substantial remuneratively" and that they tend to involve longer-term contracts.
The account excludes the contracts for the Post Office and Parcelforce Worldwide divisions.
AMV refused to confirm or deny the Tetra Pak win.