Sharrocks left his role as chief executive of Aegis Media Global Brands this summer, where he lead the Carat, Vizeum and Posterscope networks.
He joins the TV body amid transition, as it seeks to keep pace with the fast-moving landscape. Led by chief executive Justin Sampson, the focus will be on cross-platform metrics for the digital and mobile age in the form of Project Dovetail.
Barb’s 5,100 homes are in the process of being upgraded to include a web-TV meter for measuring viewing on PCs and laptops in an attempt to provide more robust data that underpins investment decisions made by the broadcasting and advertising industry of £7 billion per year.
Paul Bainsfair, director general of the Institute of Practitioners in Advertising and board director of Barb, thanked Walmsley for his "experience and wisdom" and said he had been "an excellent chair".
He went on to praise Sharrocks’ "rich heritage of business leadership" and real insight into the challenges and opportunities ahead."
Last month, Digital Cinema Media (DCM), the sales house for Odeon, Cineworld, Vue, Picturehouse and many independent cinemas, appointed Sharrocks, a former Warner Bros leader, as its first non-executive chairman.