Egon's childhood was marked by precocious intellect and an unusual detachment from social norms. He reportedly experimented on his siblings and classmates, engaging in activities that while scientifically driven were often considered strange. He began collecting spores, molds, and fungus at a young age, exhibiting a fascination with the unseen world and an aptitude for scientific inquiry that set him apart.

Egon dedicated himself to academics, earning multiple degrees in physics, engineering, and parapsychology. He focused his studies on the intersection of science and the supernatural, a field largely disregarded by mainstream academia. His relentless pursuit of knowledge led him to conduct unorthodox experiments and develop cutting-edge theories that often challenged conventional wisdom.

Egon worked alongside Peter Venkman and Ray Stantz in the Parapsychology Department at Columbia University. During this period, they conducted research on various paranormal phenomena, though their funding was often limited, and their findings were often met with skepticism. This era involved significant theoretical development, the development of early detection equipment, and a budding yet volatile friendship with Peter Venkman.

Despite their research efforts, the trio's work at Columbia University was deemed unscientific and unproductive. They were ultimately dismissed from their positions, forcing them to seek alternative means of funding and legitimizing their research. This setback proved to be the catalyst for the creation of Ghostbusters.

Egon, along with Peter Venkman and Ray Stantz, established Ghostbusters, a paranormal investigation and elimination service. His scientific expertise was crucial in developing the team's ghost-trapping technology. During the Gozer incident, Egon's quick thinking and understanding of interdimensional physics played a pivotal role in defeating the ancient entity and saving New York City. His suggestion not to cross the streams, while ultimately disregarded, highlighted his adherence to scientific protocols.

Five years after the Gozer incident, Egon and the Ghostbusters faced another supernatural threat in the form of Vigo the Carpathian. Egon's continued research into paranormal energy and ectoplasmic phenomena was crucial in understanding Vigo's malevolent intentions and developing a strategy to neutralize the possessing entity. His unwavering dedication to scientific understanding, even in the face of existential threats, remained a defining characteristic.

Following the Vigo incident, the Ghostbusters continued their work on a smaller scale, facing smaller paranormal disturbances while continuing their research. This period likely involved numerous experiments, refinements of their equipment, and the exploration of new theories in the field of parapsychology. Egon likely continued to be at the forefront of innovation in the field.

Driven by visions and growing concerns about an impending apocalyptic event linked to Ivo Shandor's mining operations, Egon moved to Summerville, Oklahoma. He meticulously researched the area, discovered Shandor's dormant gate to another dimension, and devised a plan to prevent its activation. He set traps and meticulously arranged equipment to prepare for his grandchildren to deal with the ultimate return of Gozer.

Egon Spengler died alone in his farmhouse in Summerville, Oklahoma, sacrificing himself to slow the return of Gozer. While the exact circumstances of his death are not entirely clear, it is implied that he used his own knowledge and scientific ingenuity to delay Gozer's return and protect his family from immediate danger. His death served as a catalyst for his daughter and grandchildren to uncover his research and ultimately complete his mission, cementing his legacy as a brilliant scientist and dedicated protector of humanity.