However, it was in Star Trekthat Nichols gained popularity by being one of the first African American women to be featured in a major television series. During the first year of the series, Nichols was tempted to leave the show as she felt her role lacked significance, but a conversation with Dr. Martin Luther King, Jr. changed her mind. Dr. King personally encouraged her to stay on the show, telling her that he was a big fan of the series and told her she "could not give up"... for she was playing a vital role model for young black children and women across the country. There is a popular urban myth that King had spoken to Nichols after seeing the "Kiss Scene" on the episode Plato's Stepchildren. An impossibility, given that this episode premiered several months after his murder. After the first season, Uhura's role on the series was expanded beyond just manning the communications console.
Former NASA astronaut Mae Jemisonhas cited Nichols' role of Lt. Uhura as her inspiration for wanting to become an astronaut and Whoopi Goldberg has also spoken of Nichols' influence.
In her role as Lt. Uhura, she participated in the first interracial kiss on U.S. television, with Canadian actor William Shatner (as Captain James T. Kirk) in the 1968 Star Trek episode "Plato's Stepchildren". The scene provoked protest and was seen as groundbreaking, even though the kiss was portrayed as having been forced by alienmind control. The episode was not telecast in some Southern cities as a result of the protests in those states; nevertheless, it caused many viewers to contact the broadcaster and the majority of the feedback of the incident was positive. It was over twenty-five years before it was broadcast on British television