Mathers replaces former Design Council chief executive David Kester, who announced his resignation from the role in April, and left the organisation in June.
Mathers starts as chief executive tomorrow, initially for one day a week, before moving to a full-time role at the end of October.
Design Council chief operating officer Madeline Denmead has been in charge of day-to-day running of the organisation in the interim period.
Mathers has been chief executive of Holmes & Marchant since 2009. Prior to that he was chief operating officer of Blue Marlin and he has also held senior roles at Fitch and Enterprise IG.
He was also president of the DBA for three years, between 2004 and 2007.
Holmes & Marchant will not be appointing a new chief executive. Lloyd Northover Group chairman David Worthington, Holmes & Marchant managing director Simon Gore and Lloyd Northover managing director Rebecca Price will be taking over Mathers’ responsibilities.
In addition, Holmes & Marchant will be moving from its Marlow office to join MSQ sister company Lloyd Northover in central London.
Mathers says, ‘I’m very pleased, and excited, to be joining the Design Council. It’s an organisation I have worked with, and supported, for a long time and it has a key role to play in the UK over the coming years.
‘I look forward to helping build its importance as an independent champion of the power of design.’
Design Council chairman Martin Temple says, ‘John’s impressive experience will add real value to our work in stimulating innovation, improving our built environment and tackling complex social challenges.’