As automobiles replaced horses and the country became more industrialized, through World War I and the Roaring Twenties, the Grumbachers continued to meet their customers' needs. The store grew bigger and, in 1929, the company was incorporated as S. Grumbacher & Son, Inc. In 1931, Max's son, Max Samuel (M.S.), joined the company. When Max the elder died in 1933, his widow, Daisy, and their two sons, M.S. and Richard, continued the business, forming a partnership in 1936. Following World War II, the family decided to expand operations. In 1946 a second Bon-Ton was opened, in Hanover, Pennsylvania. Two years later, the company moved outside Pennsylvania, acquiring Eyerly's in Hagerstown, Maryland, and in 1957 purchasing McMeen's in Lewistown, Pennsylvania. These early moves set Bon-Ton's policy of growing into adjacent areas by opening new stores and acquiring existing businesses.
The 1980s formed a period of rapid consolidation in the retail department store industry as major chains bought their competitors. The Bon-Ton Stores began the decade by opening more stores, establishing a new division, Maxwell's, and acquiring Fowler's department store in New York. When Tim Grumbacher was made CEO in 1985, the company operated 18 stores in four states. Two years later the company made a major move, buying the 11-store Pomeroy's chain from Allied Department Stores. That purchase made it possible for the company to move into seven new markets in Pennsylvania.
In July 1994, The Bon-Ton purchased the 127-year old Adam, Meldrum, and Anderson Department Stores AM&A's based in Buffalo, NY for $42.6 million. Around the same time, The Bon-Ton also purchased Chappell's of Syracuse, New York and Hess's of Allentown, Pennsylvania. The Bon-Ton initially retained and operated Hess's flagship location up until 1996, when it closed after over 100 years of continued operation. The site was eventually demolished.
Seven years later, The Bon-Ton would expand its reach into Ohio and the lower Midwest with the acquisition of the Elder-Beerman store chain. Following an attempt to convert to a privately-held company, Elder-Beerman was offered more cash for its outstanding stock as part of the buyout. The chain currently continues as a separate nameplate.
Each chain serves a primary geographic market, though some states have a presence from more than one of the chains. Bergner's serves northern and central Illinois. The Chicagoland region is the primary market area for Carson Pirie Scott. Boston Store serves Milwaukee and other cities throughout Wisconsin. Herberger's is a dominant nameplate in Minnesota and the Great Plains region. Younkers stores operate throughout Iowa and the upper Midwest.
The buying, private brand product development and marketing functions for the group were consolidated into the NDSG's Corporate offices in Milwaukee, Wisconsin. Finance, legal and IT functions for all locations were consolidated into the Bon-Ton's corporate offices in York, Pennsylvania.
The Indiana store was converted to a Carson Pirie Scott location in February 2007, while the Ohio store was converted to a women's Elder-Beerman store in its mall. The three Michigan locations (all in the Detroit metropolitan area), however, have all retained the Parisian name.