Farnan will report directly to Trinity Mirror's regional managing director John Bills and takes up his new position in the summer.
Before joining Metro, Farnan worked at GQ magazine, where he was ad director, the Evening Standard and IPC Media.
Farnan first joined Metro in 1999 from GQ as brand group head before moving up to become head of client sales and then sales director of the Associated Newspapers-owned title before he took on his current role.
His departure from Metro coincides with a restructure that will see the arrival of Simeon Adams, a director of Mediaedge:cia, as head of planning.
Bills said: "Justin has an outstanding record of achievement in a variety of publishing businesses and I have no doubt that he prove a major asset to us in the Midlands."
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