Sir David, diagnosed with Parkinson's disease in 1982, steps down after a year as executive chairman. He will, however, stay on as a non-executive director, handing over his executive responsibilities to Keith Jones, the new chief executive.
Sir David has had stints at Next and Morrisons. He joined JJB as a non-executive director in 2007 and went on to become executive chairman in January last year.
John Clare, senior independent director of the company, will become acting chairman until a replacement is found.