McGowan, who previously held the title chief executive of global clients, will be charged with leading an investment programme across the firm's brand development and innovations services at its 24 international offices.
In his previous role, McGowan was responsible for forging many of Added Value's relationships with global brands, including Levi's, Pepsi, Pernod Ricard and Nestle.
McGowan said: "This recession is far deeper and wide reaching than downturns experienced in most marketers' lifetimes.
"Consumers are demanding more tangible propositions across every category, which are placing brands under tremendous pressure to deliver real value, faster and better than the competition.
"Our continued commitment to invest in developing strategic tools and expert teams will enable us to deliver strong, more robust answers to our clients' toughest marketing challenges."
As part of that commitment, Added Value said it will launch a major digital innovation and research platform in the summer to better capture conversations, views, opinions and experiences from consumers and experts.
McGowan joined Added Value in 1989 when it was a small start-up agency employing 10 consultants. In 1994, he was made board director of the business, joined the group board in 1996 and was appointed group chairman in 2001. He has been CEO of global clients since 2004.
Added Value has a presence in 14 countries and is part of WPP's Kantar Group.