Mischief won the brief during a pitch process that included Edelman, Lexis and Blue Rubicon’s consumer arm Surname & Surname.
The agency will work on the launch of Land Securities' new £350m retail and leisure development Trinity Leeds, which is due to open in March 2013.
The move comes after PRWeek revealed Kent shopping destination Bluewater is in talks with consumer agencies as it faces increased competition from Westfield's Shepherd's Bush and Stratford City centres.
Sean Curtis, head of marketing, b2b at Land Securities, said: 'We will work with Mischief to ensure we put Trinity Leeds firmly on the map for shoppers, retailers and visitors alike.'
Trinity Leeds will comprise of more than 120 retailers and restaurants, including Topshop, Next, Marks & Spencer, Mango, Hollister and Superdry.
Mischief is charged with using its retail and fashion PR credentials to help the venue ‘propel Leeds up to fourth position in the UK’s retail hierarchy’.
Ben Dutton, Mischief director, said: ‘We will focus on driving fame and making Trinity Leeds a leading destination brand.’
The agency has also been asked to help position Trinity Leeds as a ‘dynamic, evolving shopping experience’ and work on it being seen as a retail beacon for the UK.
Trinity Leeds will be the biggest shopping centre launch since the opening of Westfield's Stratford City complex in 2011 and the only major shopping centre currently being constructed in the UK.
The economic climate has seen shopping centre construction hit a 50-year low, with only 31,500 sq m (339,063 sq ft) of new retail centre space being developed in 2012.