The move means a split with Manchester agency Brazen after a four-year relationship.
London start-up Mischief was hired after a two-way pitch against Surgery PR (PRWeek, 20 October).
Cheshire-based Onitsuka Tiger said it parted company with Brazen as it wanted an agency based closer to its flagship store in Newburgh Street (near Carnaby Street) and London media.
The campaign will target 22 to 32-year-old urban men, focusing on the brand's Japanese heritage.