Headquartered in Greenlawn, Long Island, New York, since 1955, it had facilities in several other locations in Long Island, including its Wheeler Laboratories facility in Smithtown, New York, manufacturing plants in Riverhead and Little Neck, NY, and a division in Braintree, Massachusetts.

Hazeltine Corporation also developed and licensed many of the basic concepts of the NTSC color television system.

Several improved models followed, including the popular Hazeltine 1500, which found use in the emerging microcomputer market in the late 1970s.

The company eventually sold the terminal line to a short-lived third party called Esprit, which was managed by former Hazeltine employees.

[3][4] In 1990, Emerson spun off its Government and Defense Group, including Hazeltine, to form ESCO Electronics Corporation.