Cincinnati-based Kroger announced last month that it would buy Roundy's for about $800 million, which includes debt.
Kroger's completed its tender offer to purchase all outstanding shares of Roundy's common stock for $3.60 per share in cash.
"We look forward to bringing together the best of Roundy's and Kroger for our customers and associates," said Bob Mariano, who will continue to lead Roundy's as president and CEO. He has served as chairman, president and chief executive officer of Roundy's since 2002. "Our merger with Kroger will help us continue to exceed our customers' expectations."
Kroger said it doesn't plan to close any stores and Roundy's headquarters will stay in Milwaukee.
The companies also vowed that local Mariano's grocery stores will remain the same, despite the sale of the rapidly growing chain to Kroger Co.
"This merger blends Roundy's complementary markets with Kroger's strengths in scale and merchandising," said Rodney McMullen, chairman and chief executive officer of Kroger. "Our future together is bright, and we look forward to learning from each other as partners. Most of all, we want to welcome each of Roundy's more than 22,000 associates to the Kroger family of stores."
Also on Friday, Roundy's shares will cease to be traded on the New York Stock Exchange.
Kroger, one of the world's largest retailers, employs more than 422,000 associates who serve customers in 2,774 supermarkets and multi-department stores in 35 states and the District of Columbia under two dozen local banner names including Kroger, City Market, Dillons, Food 4 Less, Fred Meyer, Fry's, Harris Teeter, Jay C, King Soopers, Mariano's, Pick 'n Save, QFC, Ralphs and Smith's.
The company also operates 786 convenience stores, 326 fine jewelry stores, 1,360 supermarket fuel centers and 37 food processing plants in the U.S. Recognized by Forbes as the most generous company in America, Kroger supports hunger relief, breast cancer awareness, the military and their families, and more than 30,000 schools and community organizations. Kroger contributes food and funds equal to 200 million meals a year through more than 100 Feeding America food bank partners.