Frank H. McIntosh founded McIntosh Laboratory Inc. in 1949. For ten years prior to entering this field, he worked at the Bell Telephone Laboratories in New Jersey, and during World War Two was head of the Radio and Radar Division of the War Productions Board. After the war, McIntosh set up a small consulting business in Washington designing radio stations and sound systems. His business required high power, low distortion audio amplifiers, but none of the products on the market at the time satisfied McIntosh’s needs. In 1946, he hired Gordon Gow as an engineering assistant to help him design and produce such an amplifier. In 1949, the company name was patented, and Gow was made executive vice president in 1950.

The early McIntosh amplifiers had enhanced performance, with a wider bandwidth and lower distortion than most of their competitor's product. During the 1950s, the company grew, and products began to appear in Hi-Fi and electronic catalogs and at audio fairs. The range of products also increased, with the first preamplifier produced in 1950, the first McIntosh tuner ( the MR55), in 1957, and a power amplifier kit in 1960.

The 1960s signalled the peak of McIntosh production. New and improved amplifiers, preamplifiers, receivers and tuners were added to the market every year, and, as consumer interest grew, the McIntosh name became a respected and well-known addition to the hi-fi market. This success continued into the 1970s, with a new factory being added and new products developed.

Frank McIntosh passed away in January, 1990, at the ripe old age of 83. In August of that year, McIntosh was purchased by Clarion of Japan for $US 28.6 million and in 2003, Clarion sold out to D&M Holdings based in Tokyo, Japan (who also own Marantz and Denon).

In 1995 McIntosh reissued two of their classic valve models; the MC275 power amplifier (the original version was produced from 1961 to 1970) and the C22, the last of their valve preamplifiers. In 1999, to mark the company's 50th anniversary, McIntosh released the all-new valve-powered MC2000 Commemorative Edition, of which only 559 were made (selling for $15,000 each!) and since 2000, several other new valve-powered hi-fi components have been released.

McIntosh are still producing high-quality audio components for the home and car.