The account win comes after months of speculation over the Army's review, which, after being originally delayed by six months with six agencies battling it out, was then dropped altogether in April.
In August, the Army made the decision that the review would be restarted from scratch with WPP Group's Ogilvy & Mather in New York and Omnicom Group's BBDO in Atlanta shortlisted along with McCann Erickson and Publicis Groupe's Leo Burnett.
McCann Erickson will take over from Leo Burnett , which has handled the account since July 2000. The account will be run by McCann Erickson in New York.
McCann Erickson has won the contract based on a five-year performance-related basis, with a base period of two years and three optional one-year renewals.
The contract will involve McCann Erickson coming up with an ad strategy and a campaign comprising television, print, radio, online, direct marketing, promotions and events for the US Army and US Army Reserves.
The new campaign is looking to make up for poor numbers of recruits signing up to the US military. At the end of September the Army was 7,000 short of its target of 80,000 new recruits to start basic training.
Last month, Interpublic Group, which owns McCann Erickson and Lowe Worldwide, posted a quarterly net loss of $101.5m.
McCann Erickson lost the $315m Lowe DIY store account to Omnicom Group's BBDO, and OMD and Interpublic lost the €1.5bn L'Oreal account, which has moved to ZenithOptimedia, as well as the $3.2bn General Motors account.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum.