Susan Storm, originally known as the Invisible Girl and later the Invisible Woman, debuted in Marvel Comics' Fantastic Four #1 (November 1961), created by Stan Lee and Jack Kirby. As a founding member of the Fantastic Four alongside her brother Johnny Storm (the Human Torch), her fiancé Reed Richards (Mr. Fantastic), and Ben Grimm (the Thing), she gains her powers from exposure to cosmic rays during an unauthorized space flight. Initially able to render herself and objects invisible, Sue is depicted in the early 1960s with blonde hair, a blue team uniform, and a more supportive, nurturing role within the group, often utilizing her invisibility for stealth and reconnaissance in battles against threats like Doctor Doom and the Mole Man.

Throughout the 1960s, Sue's character demonstrates growing confidence and capability, evolving from a frequently endangered figure to a more assertive hero. Her powers expand significantly with the introduction of invisible force field generation in Fantastic Four #22 (January 1964), enabling her to create protective barriers and offensive projectiles, which markedly enhances her combat contributions. She navigates complex dynamics, including the unrequited romantic pursuit by the Sub-Mariner, while maintaining loyalty to Reed and the team, reflecting themes of resilience and familial bonds central to the series.

Sue experiences profound personal developments in the latter half of the decade, culminating in her marriage to Reed Richards in Fantastic Four Annual #3 (1965), a celebrated event interrupted by numerous villains yet affirming her commitment. By 1968, she announces her pregnancy, leading to the birth of their son, Franklin Richards, in Fantastic Four Annual #6 (November 1968), amid cosmic conflicts involving Annihilus. These milestones underscore her transition toward balancing heroism with domestic aspirations, establishing her as an integral, empowering presence in Marvel's Silver Age narratives.