He was previously the tournament director of the BNP Paribas Open at Indian Wells.
He will replace Stacey Allaster, who said last month that she was standing down after six years in charge.
Mr Simon will begin his duties immediately as he winds down at Indian Wells, and should be full-time in the new job by 30 November.
"Steve Simon, with his successful career leading one of tennis' most prestigious tournaments, is the perfect person to run the WTA," the WTA board said.
The appointment was backed by WTA founder Billie Jean King, and supported by players Serena Williams, Maria Sharapova and Caroline Wozniacki.
The Women's Tennis Association (WTA) has named Steve Simon as its new chief executive.