The brand dates to 1967. In its earliest years, the brand was guaranteed to last "forever", that is, as long as the original owner still owned the car in which it was originally installed, far more generous than traditional pro rata battery warranties. When drivers began to keep automobiles for longer periods than had been traditional previously (due to both their rising cost and hence longer financing contracts, and their improved durability), the cost of this policy became prohibitive and it was discontinued. However the brand line was kept and expanded; it now includes medium-priced, medium-duty batteries as well as the premium-priced, heavy duty line with which it was begun, and in recent years has been expanded to include other non-automotive batteries as well. It is used on batteries for motorcycles, boats, golf carts, garden tractors, and snowmobiles.
Some of the batteries themselves are manufactured by Johnson Controls Inc. which also manufacture Duralast, Varta, AC Delco, as well as 20 other brands. For a time, DieHard batteries were also manufactured by Exide, however they have switched back to Johnson Controls. The DieHard Platinum line is made by EnerSys, which also makes its own line of premium Odyssey batteries manufactured in the United States.
The DieHard brand is also used on battery chargers, booster cables, power inverters, alkaline batteries, work boots, and more recently the batteries for Craftsman power tools.