While attending Columbia University Richards rented living quarters at the Manhattan boarding house owned by the aunt of a young girl named Susan Storm. Though she was still only a child, no more than twelve years old, Susan fell in love with the older Richards, much to his embarrassment.

Three years before Reed Richards tested his starship, his father mysteriously disappeared. In fact, Nathaniel Richards had devised a time machine which he had used to attempt to journey into the future of his own world. However, the machine actually transported him to an alternate Earth with a history considerably different from our own; Reed Richards would be reunited with him while visiting this alternate Earth years later. But before Nathaniel Richards left his own time line, he made arrangements that left two billion dollars to his son. Reed Richards spent most of this money on his project to build and launch his starship. This project, based in Central City, California, received further funding from the federal government.

Reed Richards recruited his old friend Ben Grimm, who had become a successful test pilot and astronaut, to pilot the starship. Susan Storm, who was now an adult, joined Richards in California. Richards and Storm were engaged to be married.

Shortly before the starship was to be launched, Richards used his scientific knowledge to defeat the extraterrestrial being Gormuu, who had intended to conquer Earth. Richards' encounter with Gormuu strengthened his resolve to finish the starship, which he saw as a first step in making it possible for mankind to defend itself from extraterrestrial threats.

However, the federal government then threatened to withdraw its funding from the project. Richards decided to take the starship on a test flight himself before the funding was withdrawn. Grimm was opposed to the idea, warning that the starship's shielding might prove inadequate protection from intense radiation storms. Nevertheless, Grimm was persuaded to serve as pilot, and Susan Storm and her adolescent brother Johnny insisted on accompanying Richards as passengers. The four friends stole onto the launch facility, entered the starship, and blasted off. They intended to travel through hyperspace in the ship to another solar system and back. However, unknown to Richards, a solar flare caused Earth's Van Allen radiation belts to be filled temporarily with unprecedented, ultra-high levels of cosmic radiation. Since the ship was designed to shield against ordinary levels of radiation, the cabin volume was subjected to intense cosmic ray bombardment, which irradiated the four passengers and wrought havoc on the ship's controls. Pilot Grimm was forced to abort the flight and return to Earth.

Once back on Earth, the four passengers discovered that the cosmic radiation had triggered mutagenic changes in their bodies. Reed Richards discovered that he could become malleable and elongate his body at will. Richards convinced the three others that the four of them should use their newfound powers for the good of humanity as members of a team he named the Fantastic Four. Richards, who became the team's leader, named himself Mister Fantastic, while Ben Grimm, Susan Storm, and Johnny Storm named themselves the Thing, the Invisible Girl (later Invisible Woman), and the Human Torch, respectively. The profits from Richards' patents and royalties funded the team's activities.

Under Richards' leadership the Fantastic Four has become Earth's most honored team of superhuman adventurers, and has saved the world from conquest or destruction many times. Richards eventually married Susan Storm, and they now have a son, Franklin.

After many years, Reed joined his wife in semi-retirement from their superhero career. They tried to raise their son Franklin in a relatively normal environment, but soon, Franklin was kidnapped by the villains Nanny and the Orphan-Maker at the same time that New York was undergoing a demonic invasion. Richards and his wife teamed up with Captain America (then, the Captain) and other heroes to reform the team Avengers, which had then recently gone on hiatus. Richards, however, continually disrupted the Avengers' team dynamic with his natural penchant for leadership. Richards and his wife soon left the team and rejoined the Fantastic Four at their base.

Since then Reed and the rest of the Fantastic four have continued to protect the world from every threat they can.

Due to the great malleability and elasticity of his molecular structure, Mister Fantastic is able to absorb the impact of any type of man-made ballistic projectile by deforming his body along the path of the projectile's trajectory at the point of initial impact. After his body absorbs the kinetic energy of a ballistic projectile's impact, he can expel the object back along its trajectory by flexing like a trampoline if he is adequately braced. He can enclose and absorb the energy of a large explosive, on the order of 8 to 12 pounds of TNT (excluding exotic, high density explosives). Such shocks to his system are physically exhausting.

Mister Fantastic's transformation to a malleable state is reflexive and nearly instantaneous: if he was at his normal form and taken unaware by machine gun fire, his body would still absorb the bullets' impact through radical deformation. Mister Fantastic's skin is virtually impervious to laceration or punctures unless he wilfully relaxes his reflexive control over small areas of his body. In that case, scalpels and ordinary needles can penetrate his skin.

Reed has also engineered numerous dimensional and interstellar exploration devices. His research into higher-dimensional physics produced gateways capable of accessing alternate realities such as the Negative Zone. These portals have enabled countless exploratory missions but have also brought Reed into conflict with powerful beings such as Annihilus, ruler of that antimatter universe.

Within the Fantastic Four’s headquarters Reed maintains laboratories filled with experimental equipment designed for cosmic and molecular research. These facilities allow him to construct devices capable of analyzing alien technology, containing dangerous energy sources, and even manipulating fundamental forces of nature. Over the years he has produced everything from molecular rearrangers and matter converters to containment fields powerful enough to restrain cosmic-level threats.

Reed’s inventions also include specialized protective uniforms composed of unstable molecules. These suits automatically adjust to accommodate the unusual powers of the Fantastic Four. In Reed’s case the fabric stretches and contracts with his elastic body without tearing, allowing him to utilize his powers freely while maintaining protection against environmental hazards.

In addition to exploration and defensive technology, Reed has built numerous analytical devices designed to observe and measure cosmic phenomena. These instruments allow him to track interdimensional disturbances, detect extraterrestrial signals, and monitor unusual energy signatures across vast distances. Such technology has frequently given Earth advance warning of approaching threats.

Although Reed rarely carries traditional weapons, he has occasionally developed devices capable of neutralizing powerful adversaries. These inventions typically rely on energy manipulation, gravitational control, or dimensional displacement rather than destructive force. Reed prefers solutions that contain or redirect threats rather than simply destroying them.

Perhaps Reed’s most significant technological achievement is his ability to combine theoretical science with practical engineering. His inventions have enabled travel across galaxies, communication with alien civilizations, and exploration of realities beyond the known universe. In many ways the technology he creates is not simply equipment but an extension of his relentless curiosity about the structure of existence itself.