The role will see Desai, currently the network's operating director for Unilever's worldwide business, focus on all Southeast Asia Pacific territories, including Australia and New Zealand but excluding China and India.
Desai's role will extend to include leadership of the Lowe Singapore office.
Desai will also retain his leadership role on the network's Unilever business. Lowe is Unilever's biggest agency, handling over 20 key Unilever brands globally.
Lowe & Partners chairman Tony Wright said Desai's promotion would further strengthen the presence Lowe has in the region.
"We are already amongst the top five agencies in most countries in this region," he said. "However, our reputation as a regional network has been very small. Lowe has been a well-kept secret for too long. We want to make a statement that we are fully in the game as a large and powerful regional agency."
With over 15 years within Lowe, Desai's experience has spanned across large multinational clients, including Unilever, InBev, J&J, HSBC, Columbia Tri-Star and Nokia. He has been based in Lowe offices in India, UAE, Lebanon and Thailand. Currently based in Singapore, he will continue to direct Lowe teams across the Unilever Asia business.
When we decided we needed stronger regional leadership, it seemed right for us to take the person who has been the best activator of our business across the region and that was Rupen," said Wright.
"Rupen is a proven leader across the region on behalf of our clients, our agencies and our work," added Lowe & Partners CEO Michael Wall. "Lowe has a competitive and compelling footprint in Asia and we believe Rupen can help us build on this strong foundation as we look to accelerate our growth and capabilities."