Lewis has been promoted to the role after spending three years as senior vice president for central and eastern Europe.
He replaces Keith Weed, who was promoted in March this year to the role of group vice president of Homecare.
Lewis started at Unilever in 1987 as a marketing trainee, holding several management roles before becoming company operations manager in 1993.
In 1996 he was appointed marketing director for Unilever Argentina and regional innovation leader for Household Care in Latin America. In 1999 he moved to Unilever Indonesia as MD of Personal Care and regional innovation leader for Personal Care in south east Asia.
Lewis said: “I felt a great sense of pride when I was asked to lead Unilever UK HPC. This is where my career began and I still see it as the flagship of Unilever’s global HPC business.”