Raised on a ranch in the San Fernando Valley, Brainard taught himself technology. He was an apprentice telegrapher and radio operator, worked on a merchantman, joined a technical crew for C. B. DeMille that developed servo-coordinated cameras for films such as Ben Hur; did electro-hydraulic work in the early aircraft industry at Vultee, Northrup, and Hughes. His experience in tracer control in the aircraft industry led him to advanced machine-tool development and he was supplied as a part-time consultant to the Vance NC machine-tool program at Wright Field.
Hughes planned a parts-making line that would have three machine tools with a Hughes control and contracted with Kearney & Trecker to develop the line and tool changer for the machines. Brainard moved with the contract to K&T as Director of Technical Operations in 1956. The contract was terminated when the Hughes control proved unsatisfactory and Brainard headed the K&T team that designed the tool changer and the Milwaukee-Matic II with a GE control, a development that changed the nature of manufacturing. A series of larger machining centers, the Gemini (a single remote computer-controlled machine tool), and a computerized manufacturing system for Allis Chalmers followed. He retired in 1969.