The niche fashion retailer runs 58 stores and concessions throughout the UK. Yusuf said the brand has the potential to become international. She said: 'It's a good company and my job now is to make it a great company. I wanted to join a company with huge growth potential, where I could contribute to every area from the design handwriting to the shop fit-outs.
Before Marks & Spencer, Yusuf was Warehouse managing director.
Set up in 1994, East has doubled in size over the past three years. It is due to open two more stores in the next three months, in Farnham and Dundrum.
East chairman Clive Pettigrew said: 'In ten years we've grown East from nothing into a well known high street fashion store. Yasmin Yusuf has the skill and expertise to take the company to the next level.'