Robert Bush's energy was apparent in college when he belonged to both the Glee Club and the Band, performed with a dance band and a vocal combo, did a program on WBAA, and kept up his studies in electrical engineering. After receiving his bachelor's degree in 1949, he went to work at the Naval Ordinance Plant in Indianapolis. In 1951 he moved to Washington, D.C., where, for the next several years, he directed research and development of aircraft weapon computers at the Bureau of Ordinance.

Bush received his Doctor of Jurisprudence degree from Indiana University in 1956 and joined Cummins Engine. He established the company's first legal department which he then proceeded to manage for 24 years. During those years he negotiated 11 major international automotive joint ventures and rose to be vice president and COO of Cummins Venture Capital, a position he held for nine years before retiring in 1989.

Bush holds directorships in more than a dozen companies in the United States and abroad, including Aires Engineering Software, Transinterbank (Swiss), and Adept Robotics and is chairman of Ferrotec, a torque sensor producer. A member of the Indiana and American Bar Associations, Bush is also deeply involved in his community. He has served as president and director of the Columbus Redevelopment Commission and as a trustee of Columbus Presbyterian Church. He helped found a day care center, was a Paul Harris Fellow in Rotary, and has served on the National Judicial Council.

In 1993 he co-founded Orchard Software Corporation, a company which specializes in medical software and marketing computer systems for diagnostic laboratories.