The Penfolds winemaker also announced a fully underwritten rights issue to raise around A$486 million ($350 million) to fund the acquisition, and said it expects to grow pre-tax earnings by up to 29 percent in the year to June 30, 2016, due to strong first quarter sales.
The company said the purchase of brands including Sterling Vineyards, Blossom Hill and Piat d'Or as well as the Chateaux & Estate Wine business in the U.S. would immediately double its luxury and "masstige" - or mass prestige - net sales revenue in that country.
The deal advances a turnaround plan under Chief Executive Officer Michael Clarke, brought in last year to rethink the company's growth strategy after a disastrous foray into the U.S. saw it destroy thousands of cases of unsold low-end wine.
Clarke has instead been eyeing acquisitions of higher quality, more profitable labels in the U.S. like those in the Diageo portfolio.
The acquisition "will be a game-changer for our U.S. brands, providing us with an immediate opportunity to (increase) our growth in the U.S., Canada, Asia and Latin America," Clarke said in a statement.
The company said it plans to fund the purchase with a rights issue at A$5.60 a share plus debt. It also plans to assume capitalized leases of $48 million.
A year ago, Clarke rejected two takeover approaches for Treasury from private equity interests at A$5.20 a share. The company's shares closed at A$6.57 on Tuesday, before Treasury announced the Diageo purchase.