She joined Starfleet circa 2252, and spent fifteen years as a combat officer, participating in missions ranging from skirmishes to all-out wars. Her ability to maintain tranquil grace under pressure earned her the nickname "Ice".
By 2267, Kwan held the rank of Captain, and was assigned as the leader of the Starfleet detachment to the planet Tenkara, stationed at a base informally named "Fort Fed." In that year, Doctor Leonard McCoy was kidnapped by Tenkaran dissidents while under her protection. Kwan tried to learn McCoy's whereabouts by interrogating a captured Tenkaran named Apek, but to no avail. Later, when Kwan's second-in-command, Lt. Commander Joe Wilder, extracted information from Apek through the use of torture, Kwan reprimanded the junior officer, while at the same time believing she had to make use of the intelligence he gathered. Tragically, this information led her and her troops into a trap, and Kwan was killed in action. (TOS - Constellations short story: "Official Record")