Roderic Malcolm, eldest son of Louis Koch, joined the company after attending the University of Wisconsin. He later graduated from the University of Evansville and received an honorary Doctor of Humanities degree from the University of Southern Indiana in 1980. Malcolm began his work with the company as a machine shop foreman in the 20’s and served as the executive vice president from 1939 until his death in 1981. The Koch Planetarium was named after Malcolm for his efforts to bring a planetarium to the Evansville Museum of Arts and Science.

George Ashburn was the second son to enter the company. After his graduation from the University of Chicago, he worked in Chicago and Omaha, Nebraska and then returned to work in, and later direct, the Personnel Department of George Koch Sons. In 1953, Ashburn became the resident manager for George Koch Sons in Portsmouth, Ohio, where the company had received the largest ever sheetmetal contract to build an Atomic Energy Plant. Upon his return to Evansville in 1956, he served as vice president and industrial relations director, the position he held until his untimely death in 1959.

Robert Louis was the third son to join the family business. Bob began work in the factory, but because of his perfect manuscript, George Koch insisted he work in the Accounting Department. All work was handwritten at that time, and none of the other brothers had legible handwriting. Through his leadership, the company began selling its painting systems around the world. Bob received an honorary Doctor of Law degree from the University of Southern Indiana in 1977. Bob was very active in the community, serving on many community, bank, university, and business boards. He later became president and chairman of the board in 1962.

William Albert, the next son, entered the business in 1938 after receiving his degree from Purdue University. He helped develop and standardize industrial finishing products. He left for the Navy four years later. Following the war, he directed advertising for the various divisions and later accepted a position at a subsidiary of George Koch Sons, Santa Claus Land, located in Santa Claus, Indiana. Bill became manager of Santa Claus Land, the first theme park in the country. In 1984, George Koch Sons traded the assets of Santa Claus Land for the shares that Bill Koch and his family had in the company. He then renamed the new company the Koch Development Corporation. This company now includes Holiday World, Splashing Safari, Holiday Village, Christmas Lake Village, and the Lake Rudolph Resort.

L. J. Koch, Jr., youngest son of Louis, had been around the company with his father and older brothers since birth. He officially began his career at George Koch Sons in 1943. Following his return from the service and graduation from Southern Methodist University, he began the supervision of the company’s paint products and items for the Metalcraft florist line. In 1988 the company traded the assets of the Metalcraft business to L.J. Koch Jr. and his family for their shares in George Koch Sons. Later, L. J. renamed the company, Koch Originals, which manufactures decorative metal furniture and floral equipment.