The origins of Tullamore Dew date back to 1829, when a distillery was established in Tullamore by Michael Molloy. On his death, the distillery eventually passed to his nephew, Bernard Daly who later appointed Daniel E. Williams as the distillery's General Manager. Under Williams's watchful eye, the distillery expanded and prospered, launching the whiskey bearing his initials (D.E.W.), Tullamore Dew.
In 1954, the distillery ceased production, having, like many of those in Ireland at the time, been hit by declining sales due to a number of factors such as Prohibition, the Anglo-Irish Trade War and high taxes introduced by the Irish Free State.
In the 1960s, with whiskey stocks running low, rather than reopen the distillery, the owners opted to sell the brand to John Powers & Son, the Dublin distillers. In 1966, John Powers & Son merged with two other Irish distilleries to form Irish Distillers. In the 1970s, Irish distillers closed their existing distilleries and consolidated production at a new distillery built in Midleton, County Cork.
In 1994, Irish Distillers, then concentrating their international focus on promoting Jameson Irish whiskey, sold the brand to the C&C Group. Subsequently, the C&C Group divested their entire liqueur and spirit business (including Tullamore Dew), which was acquired by William Grant & Sons for €300 million in 2010. At which point, Tullamore Dew was still being produced under license by at the Midleton Distillery. Therefore, as expansion of the brand was dependent on the availability of whiskey from Midleton, and with significant growth envisaged, William Grant & Sons opted to construct a new distillery in Tullamore, rather than depend on outsourced production.
Construction of the distillery is to take place on a phased basis. Phase one was completed in 2014, which saw production of whiskey return to Tullamore for the first time in sixty years. The new distillery has the capapability to produce both malt and pot still whiskey. However, it does not yet have a Coffey still installed to allow the production of grain whiskey. Therefore, as Tullamore Dew is a blend of all three varieties of Irish whiskey, the grain whiskey component of the blend will continue to be sourced from Midleton until phase two is completed.
As of 2015, the whiskey sells about 950,000 cases per year (an amount that has doubled since 2005).