He left Porter Novelli, where he was global head of digital, in November 2009 to set up his own company the Magic Bean Laboratory,
Prior to this, he founded social media agency RMM, which counted the Queen as a client, and was part of the team that set up Tribal DDB London, where he was commercial manager.
Morrison will be responsible for overseeing strategy, management and activation of all social media activity across Starcom and MediaVest.
He has particular experience in social network analysis, having undertaken various research projects to understand the nature and measurability of influence.
Richard Hartell, chief strategy officer at Starcom MediaVest Group, said: 'Mat is a perfect example of how social media are blurring the boundaries between communication disciplines. He has led both internationally and locally across a range of categories and from a range of perspectives, making him one of the most rounded and intelligent social media practitioners around.'
Mat’s appointment is the latest in a series of senior digital appointments at SMG.
In the past six months the agency has invested heavily in digital talent, appointing a head of search, Rian Carsten, head of emerging platforms Oli Newton and welcoming Kirsten Nielsen as its digital development director.
SMG’s income from social media activity has increased by more than 300% in the last 12 months.
Recent activity includes creating and launching a social media platform for the Tetley Tea Folk to mark the re-introduction of the characters. This includes managing a Twitter feed for Tetley's animated brand icon "Gaffer" and creating "Tea-V", a dedicated YouTube channel featuring archive footage and highlights selected by the Tea Folk.