Havas veteran Troni will report to global chief executive Michael Wall and global chairman Tony Wright, and join the Lowe and Partners leadership team.
Wall said: "Naomi is a first-class talent, she gets our collaborative model and our vision of building a contemporary and creatively differentiated network for our clients. The creation of this new role reflects the forward momentum of our network."
She joins Lowe and Partners from Havas, where she has spent a decade in key roles across Europe, the USA and Asia.
Most recently, she served as chief executive of Havas Worldwide Southeast Asia, based in Singapore overseeing operations in that market and in Indonesia, Malaysia, the Philippines, Thailand, and Vietnam.
Prior to her time in Asia, Troni was global chief marketing officer of Havas Worldwide, based in New York, where she was responsible for leading the network’s global new business and marketing.
In 2014 she returned to Havas in the UK as managing director for global collaboration.
Troni said: "It’s an incredibly exciting time to be joining Michael, Tony and the team at Lowe as the network continues to grow in stature and scale. I’m looking forward to building on the momentum to drive growth, and working to strengthen Lowe and Partners’ positioning as a contemporary and distinctive network brand."
She will be based in London and will take up her new role later in the year.