Glenne has been asked to "develop and implement strategies which blend DigitasLBi’s industry-leading data, creative and technology capabilities", and will oversee a ten-strong team of media strategists in London and Edinburgh.
He will report into Paul Dalton, the international chief media officer, who joined the agency last year.
Glenne joined Starcom in July last year. Before this he worked on a contract basis at Carat Global as digital strategy director.
In 2012, he became ecommerce director at Gant, the luxury fashion brand. Before this he was a senior digital consultant at MediaCom in Oslo, Norway.
In 2008, Glenne launched Fashionmixology.no, an online luxury fashion boutique in Norway. This merged with My-Wardrobe.com, the global luxury fashion retailer in 2012.
Dalton said: "Lars has a remarkable range and depth of experience, with a track record of developing media strategies for some of the world’s most well-respected brands as well as valuable time spent working client-side.
"I’m looking forward to working with him to help develop media strategies which excite our clients and create growth for their brands."