"The transaction was funded by a $130 million mortgage loan while $70 million came from (the company's) own resources," Hazem al-Dosari, a Kingdom Holding Company spokesman, told AFP.
The Four Seasons Toronto features 259 guest rooms, including 42 suites.
"This transaction is in line with our investment strategy to develop hotels in selected key cities," Prince Walid said in a company statement announcing the deal.
The prince, in his late 50s, has holdings in Citibank and Rupert Murdoch's News Corporation. Forbes magazine listed him last year as the 26th richest person in the world with assets of $19.6 billion.
Kingdom Holding, of which he owns 95 percent, has stakes in Four Seasons and Fairmont Raffles Hotels International.
In December last year, Prince Walid and his KHC announced a combined investment of $300 million in the social networking site Twitter.