The account will move from The Law Firm immediately, less than a year since it was appointed in November. However, The Law Firm still holds the £22m account for sister Associated Newspapers title The Daily Mail.
The Law Firm pitched for the account along with Miles Calcraft Briginshaw Duffy and two other undisclosed agencies.
The pitch was conducted through the AAR and run by Charlie Edelman, head of marketing for the Evening Standard.
Edelman said: "The competition for the Evening Standard advertising contract was extremely close, but we felt that McCann Erickson offered the right combination of strategic insight and creative flair."
The McCanns advertising strategy is expected to expand on the Evening Standard's recent positioning as London's "quality paper" as a point of difference to the freesheets.
The paper was hit by the simultaneous launch of News International's thelondonpaper and Associated's own London Lite last September, and raised its cover price from 40p to 50p just before their arrival.
Its six-month average circulation has dropped 18% over the past year to 268,262 copies.
This article was first published on brandrepublic.com