She sang with Duke Ellington and Lionel Hampton before turning to acting. Her most famous role was playing communications officer Lieutenant Uhura aboard the USS Enterprise in the popular Star Trek television series, as well as the succeeding motion picture spinoffs, where her character was eventually promoted in Starfleet to the rank of commander.

Nichelle Nichols was born in Robbins, Illinois, near Chicago. Her father was both the town mayor of Robbins and its chief magistrate. She studied in Chicago as well as New York and Los Angeles. During her time in New York, Nichelle appeared at the famous "Blue Angel" and Playboy Clubs, as a singer. She also appeared in the role of Carmen for a Chicago stock company production of Carmen Jones.

She has twice been nominated for the Sara Siddon Award as best actress and is an accomplished dancer and singer. Her first Siddon nomination was for her portrayal of Hazel Sharp in Kicks and Co., and the second for her performance in The Blacks.

Nichols toured the United States, Canada and Europe as a singer with the Duke Ellington and Lionel Hampton bands. On the West Coast, she appeared in "The Roar of the Greasepaint, the Smell of the Crowd," "For My People," and garnered high praise for her performance in the James Baldwin play, "Blues for Mr. Charlie".

Prior to being cast as Lt. Uhura in Star Trek, Nichols was a guest actress on television producer Gene Roddenberry's first series, The Lieutenant.

However, it was in Star Trek that Nichols gained popularity by being the first African American woman 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. After the first season, Uhura's role on the series was expanded beyond just manning the communications console.

Former NASA astronaut Mae Jemison has 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 alien mind 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.

After the series ended in 1969, Nichols volunteered her time in a special project with NASA to recruit minority and female personnel for the space agency, which proved to be a spectacular success. They include Dr. Sally K. Ride, the first American female astronaut and United States Air Force Col. Guion Bluford, the first African-American astronaut, as well as Dr. Judith Resnik and Dr. Ronald McNair, who both flew successful missions during the space shuttle program before they died in the Challenger Accident on January 28, 1986.

An enthusiastic advocate of space exploration, Nichols has served since the mid-1980s on the Board of Governors of the National Space Society, a nonprofit, educational space advocacy organization founded by Dr. Wernher von Braun.

Always interested in space travel, Nichelle flew aboard NASA's C-141 Astronomy Observatory, which analyzed the atmospheres of Mars and Saturn on an eight hour, high-altitude mission. She was also a special guest at the Jet Propulsion Laboratory in Pasadena, California on July 17, 1976 to view the Viking 1 soft landing on Mars. Along with the other cast members from the original Star Trek series, Nichelle attended the christening of the first space shuttle, Enterprise, at the North American Rockwell assembly facility in Palmdale, California.

In 1994, she published her autobiography Beyond Uhura: Star Trek and Other Memories.

Between the end of the original series and the Star Trek animated show and feature films, Nichols starred in minor roles in film and TV. She portrayed a foul-mouthed madam in Truck Turner (1974) opposite Isaac Hayes. She appeared as one of Al Gore's Vice Presidential Action Rangers in an episode of the animated series Futurama. She also played the recurring role of Diane Maza in the animated series Gargoyles and played the role of Thoth-Kopeira in an episode of Batman: The Animated Series.

Nichols' brother Thomas was a member of the Heaven's Gate cult; he died on March 26, 1997 in their mass suicide.

Nichols' son is actor Kyle Johnson, who portrayed the lead in Gordon Parks' The Learning Tree.