Mathieu, who spread the philosophy of "more magic, less logic" across the business, is understood to be joining Samsung the next few months to replace Todd Pendleton, CMO of Samsung US' mobile division.
Mathieu, a regular on the conference speaker circuit, is currently global SVP marketing at Unilever. He is a keen supporter of start-ups and has spearheaded Unilever's incubation of new technologies.
The most senior marketer at Unilever after CMO Keith Weed, Mathieu speaks often about "embracing" risks and eliminating fear of failure and has been instrumental in developing the business' "crafting brands for life' strategy aka "more magic, less logic".
Unilever confirmed it was looking for a replacement as a result of the departure but Samsung has yet to officially announce the appointment.
"Marc will be leaving Unilever to join Samsung. We thank him for his achievements here and wish him all the best in his new role," a spokeswoman for Unilever said.