After completing four years of service with the U. S. Army as a 1st Lieutenant, Robert E. King received his BSEE degree from Purdue in 1946. He began his career as a student engineer with Square D, an international manufacturer of electrical equipment and electronics products. Having completed six months of product training, he became a field engineer. King's career with Square D grew and encompassed distribution, equipment sales, marketing services, and general sales. In 1970, he was promoted to product manager. In this newly created position, King supervised product planning and development activities, including the operations of headquarters sales staff in manufacturing divisions. King was then appointed as commercial vice president, and became vice president of products in 1971.

As vice president for distribution and equipment manufacturing, King was responsible for manufacturing operations at five Square D plants. He became vice president of manufacturing in 1979 and was responsible for distribution power equipment and specialty equipment groups. From 1981 to 1982, he served as executive vice president and member of the board and was involved in domestic field sales and related marketing and distribution. In 1982, King was named president of the electrical group and was responsible for all domestic manufacturing, marketing, and distribution operations. King became vice chairman of Square D Company and held that position until his retirement.

King received an honorary doctorate from Purdue in 1984.