He gets one of of those really short Wikipedia entries: Harry Wasylyk, Winnipeg inventor, sort of, of the plastic garbage bag. Other sources are a little more expansive.
Enter Winnipeg inventor Harry Wasylyk who, after the Second World War, began experimenting with a new material called polyethylene. Harry made his first plastic bags in his kitchen and supplied them to the Winnipeg General Hospital to line their garbage cans. He quickly moved his kitchen production to a plant. – Library and Archives Canada
I say Harry was “sort of” the inventor not because there’s any doubt about what he did, but because two other people seem to have come up with the same idea at about the same time.
Around the same time, Larry Hanson, an employee at Lindsay, Ontario’s Union Carbide plant began to make garbage bags to use around the plant. Union Carbide knew a great idea when it saw one. The company bought Wasylyk’s business and began producing the garbage bags from the leftover polyethylene resin piling up at its Montréal plant. Another Canadian, Frank Plomp of Toronto was also working on the same idea in the 1950s. He sold his garbage bags to hospitals and offices. Three inventors working on the same idea at roughly the same idea, and all of them Canadian!
Clearly an idea whose time had come. You just can’t keep a good environmental hazard down.