In addition to operating 18 manufacturing facilities in the United States and Puerto Rico, the company licenses its products internationally.

In response, Simmons acquired manufacturing plants in San Francisco, California; Los Angeles, California; Montreal, Quebec; Toronto, Ontario; Winnipeg, Manitoba; Vancouver, British Columbia; Elizabeth, New Jersey; Seattle, Washington; and Atlanta, Georgia.

[7] Equipment developed by Simmons in 1925 automated the process of coiling wire and inserting it into fabric sleeves, called encasements.

[7] Simmons promoted its products aggressively with ads that included testimonials from famous people such as Eleanor Roosevelt in 1927 and Henry Ford, H. G. Wells, Thomas Edison, Guglielmo Marconi and George Bernard Shaw in 1929.

[9] In 1940, Simmons introduced the Hide-A-Bed, a sofa that incorporates a fold-out spring and mattress that pull out to form a bed.

[6][7] By the post-war year of 1947, the company was back in the mattress business and started using advertising to associate its products with the Hollywood glamor of actresses including Dorothy Lamour and Maureen O'Hara.

[6] A research and development facility was established in Munster, Indiana, in 1957, building upon pioneering studies on human sleep behavior that Simmons had sponsored in the 1930s.

Shortly thereafter, the company research and development team also relocated to Georgia, to a building in what is today Peachtree Corners.

[6] Simmons underwent the first in a series of corporate mergers and acquisitions in 1979, when the company was acquired by Gulf and Western Industries.

[14] The bankruptcy court approved the deal, reducing the company's total debt from about $1 billion to $450 million.

[15] Ares and the Ontario Teachers' Pension Plan were also the owners of the Serta brand name under National Bedding Company LLC.

Ares Management and the Ontario Teachers' Pension Plan continued to own a "significant" share of company equity.