KEMET Corporation was set up in 1919 and now is based in Simpsonville, South Carolina. The company produces many kinds of capacitors, such as tantalum, aluminum, multilayer ceramic, film, paper, polymer electrolytic, and supercapacitors. Capacitors are electronic components that store, filter, and regulate electrical energy and current flow. As an essential passive component used in most circuit boards, capacitors are typically used for coupling, decoupling, filtering, oscillating and wave shaping and are used in communication systems, data processing equipment, personal computers, cellular phones, automotive electronic systems, defense and aerospace systems, consumer electronics, power management systems and many other electronic devices and systems (basically anything that plugs in or has a battery). The company also manufacturers a variety of electronic components such as, AC line filters, EMI cores and filters, flex suppressors, relays, metal composite inductors, ferrite products, and transformers/magnetics. The product line consists of nearly 5 million distinct part configurations distinguished by various attributes, such as dielectric (or insulating) material, configuration, encapsulation, capacitance (at various tolerances), voltage, performance characteristics and packaging.

In 1919, KEMET Laboratories was founded by Union Carbide Corporation to capitalize on its purchase of Cooper Research Company of Cleveland, Ohio. Cooper had developed an alloy that could be used in the manufacture vacuum tube components.

In 1958, KEMET changed its market focus to tantalum capacitor. In 1969, the company entered the market of ceramic capacitors.

In 1990, KEMET Electronics Corporation was acquired from Union Carbide and after two years, the company went public on the New York Stock Exchange under the symbol KEM. This ended all ties with Union Carbide.

KEMET acquired the tantalum business unit of EPCOS AG in 2007, Evox Rifa Group Oyj and Arcotronics Italia S.p.A. in 2008, Cornell Dubilier Foil, LLC and Niotan Incorporated in 2012.

In 2012, the company completed the acquisition of Cornell Dubilier Foil, LLC and Niotan Incorporated.

In 2017 the company announced the closing of a deal to purchase a controlling share of NEC Tokin. After the purchase by KEMET concludes on April 10, 2017, NEC Tokin will be renamed "Tokin Corporation".

KEMET Electronics Corporation manufacturers capacitors and other components for computing, telecommunications, medical, aerospace defense, and auomotive markets. The Solid Capacitor Business Group produces tantalum and ceramic capacitors. The Film and Electrolytic Business Group sells film, paper, solid organic aluminum electrolytic capacitors, wet aluminum electrolytic capacitors.

Tantalum Business Group focuses on tantalum and aluminum capacitors for computing, telecommunications, medical, military, automotive and many other industries. Ceramic Business Group focuses on multilayer ceramic capacitors. Film and Electrolytic Business Group focuses on film, paper and wet aluminum electrolytic capacitors.

In January 2014, KEMET introduced the High Voltage-High Temperature (HV-HT) Series in C0G Dielectric, improving the efficiency over competitive high temperature (200 degree) precious metal electrode (PME) and base metal electrode (BME) ceramic capacitor devices. Oct. 2013 KEMET announced the opening of the new aluminum Electrolytic Innovation Center (EIC) in Weymouth, U.K. Products made from this new center include 20 g High Vibration Screw Terminal capacitors and a Low Inductance product line under Film and Electrolytic Business. In fiscal year 2015, KEMET had 33 PhD scientists, of which 17 were focused on technology, and 501 engineers (about one half of which are in manufacturing and the other half in R&D). KEMET was granted a record number of 20 U.S. patents in fiscal year 2015.

In June 2013, KEMET won the Supplier Excellence Award for the Americas, Asia and Europe by TTI. In 2015, KEMET received the Global Operations Excellence Award from TTI.