His remit is to develop the short-term strategic direction of its marketing.
He will also oversee the £9m creative and media agency reviews, alongside brand development director Katie Spriggs.
Spriggs had been leading the review, which began shortly after top marketer Muriel Stirling was axed as brand director in a raft of senior management changes under chief executive Kate Swann (Marketing, January 15).
An agency decision is expected before May 1, with six creative agencies fighting it out: DDB London, Clemmow Hornby Inge, Delaney Lund Knox Warren, Euro RSCG London, WCRS and J Walter Thompson.
Incumbent Abbott Mead Vickers BBDO declined to repitch.
MediaCom, Walker Media, Universal McCann, Carat and incumbent Starcom Motive are pitching for the media account.
Robertson will take the role for up to six months, while WH Smith recruits a permanent marketing director.
He will report to acting commercial director Sue Wharton, who will resume her role as trading development director when a successor is found.
Robertson had been at B&Q parent firm Kingfisher for ten years. He left in September 2003.