After her return to Earth, Jemison resigned from NASA in March 1993 with the intention of starting her own company. NASA training manager and author Homer Hickam, who had trained Jemison for her flight, later expressed some regret that she had departed.
Jemison served on the board of directors of the World Sickle Cell Foundation from 1990 to 1992. In 1993, she founded The Jemison Group Inc., a consulting firm which considers the sociocultural impact of technological advancements and design. Jemison also founded the Dorothy Jemison Foundation for Excellence and named the foundation in honor of her mother. One of the projects of the foundation is The Earth We Share, a science camp for students aged 12 to 16. Founded in 1994, camps have been held at Dartmouth College, Colorado School of Mines, Choate Rosemary Hall and other sites in the United States, as well as internationally in South Africa, Tunisia, and Switzerland. The Dorothy Jemison Foundation also sponsors other events and programs, including the Shaping the World essay competition, Listening to the Future (a survey program that targets obtaining opinions from students), Earth Online (an online chatroom that allows students to safely communicate and discuss ideas on space and science), and the Reality Leads Fantasy Gala.
LeVar Burton learned that Jemison was an avid Star Trek fan and asked her if she would be interested in being on the show. In 1993, Jemison appeared as Lieutenant Palmer in "Second Chances", an episode of the science fiction television series Star Trek: The Next Generation, becoming the first real-life astronaut to appear on Star Trek.