Warren Scarr takes up role following departure of Jo Kenrick as part of a board restructure last year.
Previously director of brand advertising within the B&Q marketing department, Mr Scarr has been promoted to the position of marketing director.
The move follows a restructure of the DIY chain's marketing department at board level, which saw the departure of former marketing director Jo Kenrick at the end of December last year.
It was originally announced that Rob Bacon would join the team from his position as chief operating officer at Carphone Warehouse.
He was expected to assume the title of customer and employee brand director in a bid to 'bring together customer and staff agendas'. Mr Bacon will not be making the move to B&Q.
Mr Scarr's new role is an expansion of his previous position, where he is now responsible for the whole marketing function at B&Q, including advertising, in-store communications and brand marketing.
He reports to commercial director John Colley.
B&Q announced a review of its £40m advertising contract in January. A shortlist of agencies is being drawn up, with a new appointment expected by summer.