The appointment sees Magna, a joint venture between Interpublic's media agencies Initiative Media and Universal McCann, broaden its offering beyond its traditional focus of TV and radio sales.
Jeans will report to Magna Global's UK chairman Mick Perry, who has been responsible for all broadcast negotiations since its launch in 2001.
A former chief operating officer at Initiative, Jeans was managing director of AMRA, the independent regional press sales house, before he joined the agency.
Jerry Hill, Initiative's group chief executive, said: "Roy has terrific credentials for this role and will add enormously to Magna's capabilities. Magna can now broaden its remit in leveraging our billings further for the continued benefit of our clients."
Jeans will continue in his role as managing director of the Unilever Europe account at Initiative, responsible for the FMCG giant's media investment across 16 countries, while his responsibilities are gradually transferred to his team over the coming months.
Chris Shaw, Universal McCann's European vice-president and regional director EMEA, said: "We are delighted to have been able to appoint Roy to this important post, which adds a multimedia dimension to Magna's offering in the UK."
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