Harris will be responsible for driving news business and the agency’s commercial development. He will also be charged with ensuring the agency has the best people working across its portfolio.
Barnes, meanwhile, will work with the chief strategy officer, Martyn Stokes to deliver integrated communications solutions for M/Six clients that take advantage of developments in technology and digital trading.
As Harris and Barnes take over more of the day-to-day running of the agency, working alongside the wider executive committee, Jess Burley, the chief executive, will be able to focus on the strategic director of M/Six.
In the past 12 months, the M/Six business has grown following the capture of the News International planning and buying account combined with the expanding business needs of clients such as TalkTalk and Virgin Money.
Harris has been at the agency, previously known as MCHI, since March 2010. After beginning his career at MediaCom and Carat, he worked at Zed Media for five years, rising to business director.
Barnes joined MCHI as digital performance director in October 2010 and was promoted to director of digital in September 2011. His career includes stints at Response One, Vizeum and Starcom MediaVest Group.
Burley said: "Particularly because we’ve grown in size, we need to create clarity about who does what, both from an external point of view and internal point of view so clients and staff know who to go to."
M/Six has also promoted Dan Keat, who joined the agency as its first head of broadcast in August 2012, to the board as investment director.
This article was first published on campaignlive.co.uk