After graduating from Cornell, Kennedy joined Union Carbide as a trainee at the division's Edgewater Research Laboratory in Cleveland, Ohio.[3] In 1977 Kennedy became president of the Linde division of the company and built a $29 million industrial gases complex in Niagara Falls, New York.[4] He was elected a senior vice president in 1981, and an executive vice president in 1982.[2]
In July 1985, Kennedy and Heinn F. Tomfohrde III, both executive vice presidents, were appointed as co-presidents of Union Carbide, sharing the responsibilities of Alec Flamm, the former president and chief operating officer who became vice chairman.[5] Kennedy became the head of Carbide's plastics and chemicals businesses, while Tomfohrde, became head of its industrial products and services businesses.[6]
In March 1986, he became chief executive officer and,[7] in December 1986, chairman, succeeding Warren M. Anderson in both roles.[8][9] Under Kennedy's tenure, "the company trimmed its operations to focus on petrochemicals, its core operations."[10] In 1990, he was succeeded as president by H. William Lichtenberger, president of Carbide's chemicals and plastics unit.[11] Kennedy continued as chairman and chief executive.[11]
He retired as chief executive in 1995 and was succeeded by William H. Joyce, chief operating officer and president since 1993.[12] Kennedy continued as chairman until he fully retired from the company on December 31, 1995.[12][13] He also served as a director of Kmart Corporation, Lion Ore Mining International Ltd., Sunoco, Inc., and Union Camp Corporation.[2]
On January 28, 1956, Kennedy married Sally Duff. Together, they were the parents of Robert B. Kennedy, Thomas Kennedy, Kathleen Kennedy and Melissa (née Kennedy) Jurick.[1]