Following the integration of General Foods with Kraft Foods Division, he was promoted from vice president and division manager at General Foods to president of Kraft USA and Oscar Mayer. By 1994, Kilts had risen to executive vice president at the Worldwide Foods Division of Philip Morris.
In 1997, he left Philip Morris to found his own investment firm, JMK Investments. He soon re-entered the corporate ranks in 1998 when he joined Nabisco, Inc. as president and CEO. In 2001, Kilts took the helm of the Gillette Company. As chairman and CEO, he was the first outsider to run Gillette in nearly 70 years. Kilts has served as a member of the Council on the Chicago Booth and the Chicago Booth Capital Campaign Steering Committee. He also has served as a trustee to his alma mater, Knox College, as well as to the Ravinia Festival and the National 4-H Council.