The story of Hoover's Dairy began in 1926, when Edwin J. Hoover started the business from a location in St. Benedict, PA. His first and only delivery route at that time consisted of eighteen quarts of raw milk daily. Soon after, the operation moved into the basement of the family home on Bigler Avenue and Baker Street in Spangler, across from the Spangler Brewery. In 1933, Hoover began full time dairy operations, this date is often referenced as the start of the "E. J. Hoover Dairy". Growth continued, and in April of 1936, the public was invited to inspect the recent remodel of the operation which included the installation of "the latest in dairy equipment".

Continued success over the next decade necessitated further expansion, and in 1947 construction of a new dairy plant on Crawford Avenue and 4th Street was completed. This new facility, "constructed in accordance with the strict regulations of the Pennsylvania Milk Control Commission," and was "rated as one of the very finest dairy plants in the state of Pennsylvania."

Edwin and his wife Ellen's three older sons: Devon, James, and Charles served in the U.S. Army during World War II, and their fourth son, Thomas, would do the same during the Korean War. Upon their return from the service, Devon, Chuck, and Tom joined their father in the family business, which underwent a name change to "Hoover's Dairy" to reflect their involvement. Their help would be needed, as the baby boom following World War II led to an increased demand for milk products, especially deliveries to area schools for student lunches.

Hoovers wasn't the only Cambria County dairy experiencing significant growth, however; following the War, the Sanitary Dairy Company of Johnstown began construction of a new plant of its own along the Stonycreek river between Franklin and Napoleon Streets and would soon rebrand its product line as "Sani-Dairy." With the emergence of both dairies' need for increased processing capacity, a partnership was entered into between Sani-Dairy of Johnstown and Hoover's Dairy of Spangler. Hoover's processing equipment would be relocated to the new Johnstown facility, which would in turn supply Hoover's with the dairy products needed to meet their growing demand. This transition was completed by 1959, and advertisements at that time began to read, "Hoover's Dairy, distributor of Sani-Dairy Milk and Ice Cream".

By the 1960's, Hoover's Dairy was delivering their products to the entire northern half of Cambria County, and, starting in 1966, a third generation of Hoovers, Edwin and Ellen's grandsons, became increasingly engaged in the operation. In 1968, Sani-Dairy of Johnstown was purchased by The Penn-Traffic Company, which would utilize the dairy to supply their Riverside, Bi-Lo, and Big Bear supermarket chains across Pennsylvania, Ohio, New York, and West Virginia. Later that same year, Edwin Hoover retired at the age of seventy-two, after devoting over 40 years to the business since its humble beginnings in 1926.

As the business continued to evolve during the 1970's and 1980's, a new building was constructed on St. Patrick's Avenue which contained the business office and housed a portion of the company's fleet of trucks. The property of the former Burnett's Auto, along Bigler Avenue on the southern end of Spangler, was also acquired and reconfigured to meet the changing needs of the industry. This facility would become the primary hub for the business by the 1980's. On March 5th, 1985, Edwin Hoover, founder and owner of Hoover's Dairy, passed away at the age of eighty-nine and was laid to rest in Holy Cross Catholic Cemetery.

The fate of Hoover's Dairy would be sealed in 1997, when Penn-Traffic, facing financial issues, sold Sani-Dairy of Johnstown to Dean Foods of Franklin, IL for $37.5 million. In January of 1999, Dean's Dairy closed the Johnstown Sani-Dairy plant and dismissed the workers. With this move, all Hoover's Dairy operations in Spangler ceased and remaining customers began to be serviced by Dean's Dairy of Indiana, PA.