Courtney Whitmore

Courtney Elizabeth Whitmore is presented in-universe as an ordinary Los Angeles teenager who moves to Blue Valley after her mother remarries Patrick 'Pat' Dugan. Discovering Pat's past as the sidekick to a Golden Age hero and the surviving Star-Spangled Kid gear in his possession, Courtney initially adopts the Star-Spangled Kid identity in part to annoy her stepfather. Pat, a former sidekick and inventor, builds the protective robotic suit S.T.R.I.P.E. to guard and accompany her. Later, Courtney is gifted Jack Knight's Starman cosmic staff and adopts the Stargirl mantle, becoming a visible successor in a multigenerational heroic network and joining the Justice Society of America.

As a civilian Courtney is depicted as a smart, athletic, kind teenage girl from suburban Blue Valley; sources emphasize her youth, optimism, and athleticism rather than exhaustive physical detail. In costume she is known by two legacy identities: she initially wears the Star-Spangled Kid's gear (the specific original costume elements are treated as inherited equipment in summaries) and later appears as Stargirl wielding Starman Jack Knight’s distinctive cosmic staff. She is commonly accompanied by S.T.R.I.P.E., the large protective mechanized suit constructed by her stepfather Pat Dugan.

Sources consistently state Courtney has no innate superhuman powers; her capabilities derive from equipment and allies. She relies on the Star-Spangled Kid’s inherited gear, the Starman cosmic staff (a powerful, staff-type device associated with Jack Knight), and the S.T.R.I.P.E. robotic suit for defense and enhanced combat capability. Behaviorally she is characterized by youthful optimism, leadership, athleticism, and a tendency to inspire peers; narratively she engages in team operations with the Justice Society, combats recurring foes such as Solomon Grundy and Klarion, and participates in time-travel and other extraordinary plot events.