[12][13] Following a strategy that had proved successful at Loral, Garrett transformed ISC by closing deficit-ridden plants, seeking civilian markets as well as government research-and-development contracts, and acquiring defense, commercial electronics and manufacturing companies.

[12][14] In 1966, Garrett brought in his son-in-law, Harvey Blau, a former Assistant U.S. Attorney for the Southern District of New York, as General Counsel to handle legal matters and transactions.

ISC purchased 20 companies in 1968 alone, ranking second in acquisitions nationwide that year, as investor appetite for corporate conglomerates reached its peak.

[14] ISC's subsidiaries operated plants throughout the United States and Canada producing electronic devices, special purpose trucks, hardware tools, furniture, packaging and building materials.

As the 1970s progressed, the company was negatively impacted by decreased defense spending as the Vietnam War ended, and by general economic uncertainty.

[14] In addition to strengthening ISC's existing lines of business, Blau diversified revenues by acquiring companies in unrelated industries.

[24] Blau and his team renamed the company Oneita Industries, restructured its finances, and grew it to the country's third-largest maker of specialty T-shirts, tripling sales to $300 million within a few years.

[14] It grew in the 1990s and 2000s, becoming a leading manufacturer of residential garage doors in the United States and one of the suppliers of plastic films for diapers, surgical gowns, and drapes.

It received $114 million from the British Royal Air Force to supply communications equipment to upgrade Nimrod anti-submarine airplanes.

It added a home installation service for residential building products such as garage doors, manufactured fireplaces, floor coverings, and cabinetry.

An investment banker who had married Blau's daughter Stephanie in 1992,[41] Kramer had served on the company's board of directors since 1993 and was elected vice chairman in 2003.

Mehmel joined Griffon from DRS Technologies, a manufacturer of defense electronic products, systems, and military support services, which grew from $400 million to over $4 billion in sales during his tenure.

In 2008, DRS was acquired by Italian conglomerate Finmeccanica for $5.2 billion which, at that time, was the largest single acquisition of a U.S. defense company by a foreign firm.

The restructured its facilities and organizational structure, and expanded its presence in homeland security, air traffic management, and unmanned aerial vehicles.

[48] To diversify revenue stream in the home and building products division, Griffon purchased Ames True Temper for $542 million in 2010.

[46] To complement the Southern Patio brand, Griffon purchased Northcote Pottery, an Australian maker of garden decor products founded in 1897, for $22 million in late 2013.

[52] Starting in 2017, Griffon executed a series of transactions to increase shareholder value, and to reshape the company's portfolio with the objectives of better focusing and strengthening its core businesses.

This transaction, which closed in February 2018, marked Griffon's exit from the specialty plastics industry that the company entered when it acquired Clopay in 1986.

[57] In the United States, Griffon acquired cleaning products manufacturer Harper Brush Works from Horizon Global in October 2017 to expand the Ames line of long-handle tools.

Many of the other Ames businesses and brands, including True Temper, Garant, and Union Tool, can trace their histories back directly or through predecessor companies to the 1800s.

Planters, landscaping and lawn accessories brands include Southern Patio, Northcote Pottery, Kelkay and Dynamic Design.

President Donald Trump visited the Ames wheelbarrow and manufacturing plant in Harrisburg, Pennsylvania on May 7, 2017, to commemorate his 100th day in office while highlighting his emphasis on buying products that are made in America.