In 1935, Gibson enlisted musician Alvino Rey to help develop a prototype pickup with engineers at the Chicago Lyon & Healy Co. Later that year, the project was moved to Gibson's factory where Walter Fuller finalised the distinctive hexagonal design. The new pickup was first used on a 1935 lap steel model. The pickup was put on an F-hole archtop guitar, called the ES-150 (ES - Electric Spanish). The first ES-150 shipped from the Gibson factory in Kalamazoo, Michigan, on May 20, 1936.

Jazz musician Charlie Christian was quick to exploit the potential of an amplified ES-150 to cut through the rest of the big band, allowing his solos to be heard. The ES-150 was to become known as the Charlie Christian model. The ES-150 had a bound spruce top with sunburst finish, maple back with mahogany sides and neck.  The fingerboard was rosewood with pearl dot inlays. Bridge was an adjustable rosewood jazz style with a trapeze tailpiece. It had a volume and a tone control for the single coil pickup.

Around 1319 of these first version ES-150s were made from 1936 to 1940. A second version was made from 1940 to 1956.

Source: www.gibson.com