East Side Mario's

East Side Mario's was developed through the merger between several restaurant chains and began as a subsidiary of Yesac Creative Foods (later, Prime Restaurants).

In February 1980, Sudbury, Ontario, entrepreneurs Nick Perpick, Ralph Roy and Gary Ceppetelli, opened the first Casey's restaurant. The restaurant's success prompted the opening of a second location in Elliot Lake, Ontario. The company moved to Burlington, Ontario, and introduced a fourth partner. The Casey's brand was developed by the original parent company, Yesac Creative Foods. In 1982, the first Pat & Mario's Restaurant was opened in Whitby, Ontario. The objective was to establish a takeout pizza and pasta business. The venture was successful and the Pat & Mario's chain expanded into the Toronto area, as well as into the United States, in Florida.

The first East Side Mario's restaurant was developed and built in Aventura Mall in Miami, Florida. To expand the business on both sides of the border, it was necessary for Yesac to raise capital. To do so, the collective brands of Casey's, East Side Mario's, and Pat & Mario's merged with the Lime Rickey's brand from Toronto to become Prime Restaurant Holdings Incorporated in August 1989. Prime Restaurants has become a major force in the current Canadian restaurant industry largely in part because of this acquisition. By 1993, Prime Restaurants had expanded East Side Mario's throughout the United States through an American subsidiary. Because of the high potential of this restaurant chain, the American subsidiary was later purchased by PepsiCo's Pizza Hut division ( which eventually sold ESM to Marie Callendar's in 1997), and Prime Restaurants retained exclusive rights to the Canadian trademarks. As of February 2000, Prime Restaurants had re-acquired global trademark rights to East Side Mario's Restaurants Inc. On July 22, 2002, the parent company made an initial public offer for the Prime Restaurant Royalty Income Fund, allowing for public investing in the brand.

As of 2010, three members of senior management retained 18% ownership under Prime Restaurants, with the other 82% belonging to Fairfax Financial Holdings Limited. In October 2013, Fairfax exchanged ownership of the Prime Restaurants brand, by selling to Cara Operations with a warrant and cash deal. In October 2013, Fairfax bought a minority interest in Cara Operations. Cara in turn bought, and assumed debt from, Prime Restaurants. Fairfax also contributed $100 Million in secondary warrants, declaring a loss of approximately $50 Million in the process.

East Side Mario's began a partnership with Scene in February 2015.

East Side Mario's closed its last United States location, in Livonia, Michigan, in May 2020.

East Side Mario's has produced a variety of both chain-wide and regional promotional offers. These have included local radio contests and giveaways in association with communities. Similar to other restaurant chains, East Side Mario's has a longstanding promotion that offers free meals for young children, marketed for families. The franchise has also engaged in advertising partnerships with other companies such as Budweiser. In 2010, East Side Mario's took advantage of the FIFA World Cup and launched a campaign, declaring itself as the "soccer headquarters".

In January 2010, East Side Mario's launched one of the largest 3 month long contests in Canadian casual dining history, the "Budda Boom Budda Ching" campaign. The contest totaled up to $10 million in prizes, and was created with support from East Side Mario's marketing partners Endeavour Marketing, Endo Marketing, Ron Christie Communications and Cowan & Company. This campaign was launched in conjunction with an ongoing social media strategy in which East Side Mario's uses its presence on Facebook in an effort to raise awareness of promotions among consumers.