Christine Chapel was a Human Starfleet officer aboard the USS Enterprise, under the command of Captain James T. Kirk during its original five-year mission of exploration.
Chapel began her career aboard the USS Enterprise as head nurse to Chief Medical Officer Leonard McCoy, and in doing so sacrificed a promising career in biology with several university degrees in research medicine. Chapel had abandoned her earlier career plans in the hopes that a assignment in Starfleet would one day reunite with her with Dr. Roger Korby, her estranged fiancé. Even while she sought to locate Korby, Chapel was deeply infatuated with the Enterprise's half-Vulcan science officer, Mr. Spock. While her attraction never interfered with her professional duties, it was an ongoing source of tension and bemusement throughout the five-year mission.
Following the Enterprise's five-year mission of exploration, she finished her own medical degree, and was promoted to Chief Medical Officer of the refitted Enterprise, now under the command of Willard Decker. However, when Dr. McCoy returned to the ship during the V'Ger crisis, she willingly stepped down to allow McCoy to return as Chief Medical Officer. Chapel was later re-assigned to Starfleet Headquarters as a Commander.