Dunbarton Grain Distillery was established in 1938 by Hiram Walker [Scotland] Ltd in the town of the same name, utilizing millions of red bricks—a rather uncommon building material in Scotland. The former site was previously a McMillan shipyard, and the distillery was designed in North America, with continuous stills supplied by Vulcan Copper & Supply of Cincinnati. It was the largest grain distillery in Scotland at the time. Although Dunbarton was a grain distillery, an Inverleven malt whisky distillery was also constructed within the Dunbarton complex during the same period. In 1959, Dunbarton Distillery added a Lomond still (see 'Miltonduff'). In 1965, the distillery installed the UK's first advanced distillation equipment based on an American system. In 1987, Hiram Walker was acquired by Allied Lyons. In 2002, Dunbarton Distillery was closed and has since been demolished.

Water comes from Loch Lomond, which also gives the Lomond still its name. Dumbarton uses only corn, primarily from the US and France, making the spirit intensely flavored and oily. The stills cannot process other grains, as their original design lacked sufficient copper—a purifying agent—to remove heavier compounds produced during distillation. Hiram Walker Gooderham & Worts Ltd, Canada's largest distillery (Canadian Club is its flagship brand), wanted to enter the Scotch whisky market. In 1935, they purchased Ballantine's and its large stocks of mature Scotch, but no distillery. Acquiring production facilities became essential, so in 1936 they bought Glenburgie and Miltonduff distilleries (see related entries), and later built Dumbarton distillery.