This comes after Marcel von Aulock resigned.
Booysen has been promoted from his role as head of the gaming division, the owner of Montecasino and Gold Reef City said in a statement after the market closed on Tuesday.
He will start as chief executive on July 1.
Tsogo did not provide a reason for the resignation of Von Aulock, who has led the company for six years.
The chief executive change comes as the company battles a downturn in gaming activity amid weak economic growth and political uncertainty.
Read also: Tsogo Sun expecting higher earnings
The shares declined 0.4 percent to R24.50, extending the fall for the year to 11 percent. That values the company at R26 billion.Bloomberg