As a young woman, she was a professional tennis player, and in 2028, played in the Goddard Moonbase Semifinals. Shortly afterward, she joined the United Earth AeroNav Forces. She had trouble in her early career with insubordinate behavior toward her superiors, and was transferred to four different ships. In 2030, she was transferred to a position under the command of Jason Nyere, who felt he needed her abrasiveness to keep himself from being too soft on his crew. The two quickly became close friends, and Sawyer credited Nyere for shaping her into a proper officer. When Nyere was given command of the CSS Delphinus, he brought Sawyer along as his first mate. On two occasions, Sawyer saved Nyere's life, and Nyere had saved Sawyer's on a third occasion.
In 2045, following the discovery of two Vulcans accidentally stranded on Earth, Sawyer resolved to keep an emotional distance from the alien beings, knowing there was a chance they would be ordered killed, so as to spare Nyere from carrying out the order himself.
Shortly after this incident, Sawyer was promoted to Captain and given command of the CSS Xeno. She commanded that vessel for twenty years, earning the reputation of a tough but fair commander. The Xeno was crippled by an engine room explosion in 2065, and Captain Sawyer managed to get all her crew safely away, before going down with her ship.