Péladeau was born in Outremont, Quebec (now part of the city of Montreal) in 1925. He completed a degree in philosophy from the Université de Montréal, and in 1950 completed a law degree at McGill University. He first purchased what was a struggling community paper, Le Journal de Rosemont, which he bought with a $1,500 loan from his mother. Péladeau later went on to pursue bigger and better companies through acquisition.
One notable event, and possibly the one responsible for the initial success of Quebecor, and one to which the company owes its existence to this day, is the smart business opportunity that Péladeau seized in the late 1960s. While the major Montréal French-language newspaper's employees were on strike, Péladeau created his own newspaper Le Journal de Montréal. This new tabloid-format publication was an instant success and continued to hold top spot until the mid-1990s. A few years after the first Journal he founded the Journal de Quebec and the defunct experiment Philadelphia Journal. His company, Quebecor, later acquired Sun Media chain, among other newspaper and magazine properties. Today Quebecor is the number one commercial printing company in the world.