Couche-Tard shares rose as much as 3.5 percent in morning trading after the company reported a 14 percent rise in adjusted profit.
Hannasch will take over as CEO on September 24 and Bouchard will become the executive chairman of the board, Couche-Tard said in a statement on Tuesday.
The company's net income rose 28 percent to $182.3 million, or 96 cents per share, in the third quarter ended February 2, from a year earlier.
The company's adjusted profit missed by 1 cent the analysts' average expectation of 93 cents per share, according to Thomson Reuters I/B/E/S.
Revenue fell 3.3 percent to $11.09 billion.
Couche-Tard acquired Norway-based gas station chain operator Statoil Fuel & Retail in 2012. The company also has 6,221 convenience stores throughout North America, including 4,724 stores that can dispense gasoline, as of February 2.
The company's shares were trading up 2 percent at C$86.85 on the Toronto Stock Exchange. They have risen as much as 8 percent in the past three months.
(Reporting by Sneha Banerjee in Bangalore; Editing by Kirti Pandey and Simon Jennings)