Robert B. Fenwick was born in Indianapolis, received his associate's degree from Phoenix College in Arizona, and returned to Indiana to complete his electrical engineering degree at Purdue. One of a set of identical triplets, Fenwick developed an early interest in radio and at Purdue continued his interest in short wave radio as well as being active in the Glee Club. In 1958 he graduated first in his class with a bachelor's degree in electrical engineering. He completed his master's at Stanford just one year later and earned a Ph.D. in electrical engineering from Stanford in 1963.

His interest in radio and in government communication needs led to his becoming the co-founder of BR Communications just three years after completing his degree. The company manufactured unique proprietary communications equipment for military and diplomatic use which was adopted by all United States and United Kingdom military services. He was chairman and president of the company from 1974 until 1985 and remained as chairman until the company was sold in 1988.

Fenwick quickly launched a new company, On Command Video Corporation, and now serves as CEO and chairman of the board of that corporation. The company designs, manufactures, installs, and operates a video distribution system in hotels throughout the country. On Command Video permits hotel guests to use an electronic controller to select from an on-screen menu and in seconds be watching the video of their choice.

Fenwick holds two patents related to short-wave radio and two for television-related devices. He also is an avid gardener, and his wide range of interests is reflected in his community service activities. He has served on the boards of the Electronic Association of California, Scholar Opera, and an architectural firm. Presently he is on the advisory board of the Community School of Music and Art and a member of the Board of Directors of the Peninsula Conservation Center Trust Fund. Fenwick is a member of the Institute of Electrical and Electronics Engineers, Tau Beta Pi, and Eta Kappa Nu.