The council will have an annually appointed chair and Jose Miguel Sokoloff, chairman and chief creative officer at Lowe SSP3 in Colombia, will take the role of president, effectively immediately.
Bull became one of South Africa's most-awarded copywriters before founding Lowe Bull in 1996.
He then spent two years from 2003 as chief executive of Lowe London, before being appointed chief creative officer of Lowe Worldwide in 2005.
He returned to Lowe Bull as chairman in 2006, before commencing his second stint as chief creative officer of the global network in 2009.
After leaving the New York-based role, he is to stay in the US, according to Lowe chief executive Michael Wall, who said: "Matthew wants to focus on building the next chapter in his career in the US".
Wall said: "Matthew's creative eye and big personality have been strong ingredients within Lowe for many years."