A shy man by nature Owen Reece was transformed into Molecule Man by a lab accident.

While working at an Atomic Power Plant Owen mistakenly activated an experiment device that opened a portal to another dimension. This portal caused him to be exposed to a powerful explosion of a strange radiation, the explosion horribly scarred his face but granted him immense power. What is an incredibly powerful kid to do but become a career criminal. Along with his transformation the portal allowed the powerful being known as the Beyonder to come into contact with Earth.

Reece was never the popular kid in school. Having struggled for so long, forced to follow the whims of others, Reece decided now was his time. Reece easily defeated the Fantastic Four and gained control over the Baxter Building. The Fantastic Four allied themselves with Uatu the Watcher and tried to stop Owen Reece from taking over a city. The Fantastic Four were met defeat again and were forced to leave the city in order to take down Reece. Mr Fantastic researched and studied about Reece and discovered Reece's weakness. Reece could manipulate molecules but he was unable to effect organic matter. The Fantastic Four wrapped themselves in plaster and were sent as statues by Alicia Masters. Reece believed that he could control all matter and used his powers to crush the plastered Fantastic Four. The feedback from the organic molecules caused Reece great pain and Uatu the Watcher banished the Molecule Man to a dimension where time is accelerated. Reece became very lonely and he created a "son" to comfort him. When Reece was about to die, he transferred all of his powers to the wand and gave the wand to his "son". Reece then died soon after.

Reece's creation sought revenge and made it's way back to Earth. He battled the Fantastic Four and was winning at first until the Thing seperated him from the wand. The wand ensured the existence of Reece's son and was immediately vapourized when the wand was seperated from him. However, Reece's energies were stored in the wand which allowed Reece to temporally take control of the Thing. The wand eventually was passed on to several people until the Silver Surfer discovered it. Reece recreated a new body for himself and decided to destroy planet Earth. The Silver Surfer assembled the Avengers and asked the Avengers to stop Reece from devouring the planet. The Avengers were badly defeated, the Molecule Man vaporized Iron Man's armor, Cap's shield, the Silver Surfer's surfboard and even Thor's mighty hammer. Reece eventually was comforted by Tigra and ended his evil vendetta and restored Earth back to normal.

It turned out that Reece's accident that opened the tiny portal, allowed an omnipotent being to observe the Marvel Universe. Unfamiliar with the emotional traits such as greed, good, and evil, this being, calling itself the Beyonder, wanted to find out more. The Beyonder transported several heroes and villains on a planet created by pieces of other planets and offered a prize. Whomever could win this "Secret War" could have whatever they wished for. It was during the Secret Wars that Owen met and fell in love with Volcana, another super-powered villain. He vowed to live a life at peace with her in the suberbs of Denver. Later overcome with his need for power, Volcana left him. Owen is determined to win back her affections.

Soon later, Reece was confronted by Kubik, who was actually a Cosmic Cube which developped sentient life. Kubik told the Beyonder and the Molecule Man about the Cosmic Cubes. The Beyonder and Owen decided to merge together to form a new Cosmic Cube. This new Cosmic Cube also developed sentient life and named itself Kosmos but he quickly rid himself of Molecule Man which stripped Owen of all his powers. Miraculously Volcana gained some of the powers that Owen had lost. She sought out the de-powered and depressed Owen only to find him sulking in his apartment. The A.I.M organization noticed the tremendous increase of power Volcana had and wanted to know it happened and how they can get it. A.I.M sent in their agent, Klaw, to capture her in the hopes of exploiting her. The power Volcana was imbued with kept increasing and began evolving during the conflict with Klaw. Her newly acciured powers found their way back to Owen which he used to become Molecule Man once again. Volcana and Owen easily combated Klaw but he fled when his gun hand was destroyed. This reacquisition of his power also revealed another aspect of his psyche and power. He has a dark aspect which manifests in three forms but once Volcana saw the darkness Owen had inside of him she ended their relationship. Owen was still in love with her and claimed that one day he would prove his love to her. In a later conflict Owen involving the Beyonder, Kosmos and Kubic; Owen saves Kubic who tells Owen that his true self is far more powerful than his dark aspect.

Many people from Dinosaur Colorado have mysteriously gone missing and after a politicians daughter disappears there Norman Osborn and his Dark Avengers are called in to investigate the disappearances. It is revealed that Molecule Man is behind all the disappearances and strange occurrences. Recently Molecule Man along with Zarathos, the Beyonder, Mephisto and the Enchantress have formed some sort of team or alliance and with Owen as their "leader" he begins to toy with Norman and his team. Owen and his associates are living in a world Owen created because he keeps repeating "I want to be left alone," but they are all acting weirdly. His associates even say "We're not his friends. Owen doesn't have any real friends. The world wasn't made for him. We're the friends he made. The friends he deserves. We're the friends he should have. If the world was fair." This is how Owen has always felt about himself but since the others are acting strangely and saying what Owen feels he may have created duplicates, controlling them somehow or they are trying to use him or they fear him so they befriend him. Owen has a childish demeanor and keeps referring to his fear of Reed Richards imprisoning him and other people taking "his home" away or invading. He torments each Dark Avenger individually, reminding Norman about Gwen Stacy (and she was pregnant) and how the world wants him to fail and he may have finally killed Sentry. Bob (Sentry) is in terrible pain and Owen remarks how he has "tasted" and "experienced" every type of molecule but Bob is different but he knows Osborn told him to hurt him so he vaporizes Bob, but he is sad because he thought they could have been friends. The rest are transformed or turned to statues. His teammates try to convince him to hide or leave but Owen yells he refuses to because he wants to be left alone in his home. While they observe a barrel of water (which is Hawkeye/Bullseye) they see Victoria Hand wandering around the deserted town looking for anyone. She and H.A.M.M.E.R are fearful of the powerful being that made the Avengers disappear so she lets Owen know that the United States surrenders.

Powers

Owen as Molecule Man can manipulate all forms of matter to the molecular level. He can create, destroy, change and manipulate inorganic and organic molecules. He can even control and manipulate energy and turn things into energy. Originally unable to affect organic molecules he was limited to controlling inorganic molecules. His inability was due to subconsciously created mental blocks due to his shy, self doubting and fearful life. These blocks were finally removed with the assistance of Dr. Doom and the power of the Beyonder. Molecule Man has a great deal of control of his power and he has the potential to become the most powerful person in the Marvel continuum.

He has been able to: Create ice due to water in the air (very early)

Destroy Thor's magic hammer Mjlnor, Captain America's Shield and the Silver Surfer's board but then reform them.

Create actual beings or elaborate likenesses , his own realms or worlds, force fields and energy beams.

Recently it has been seen he can read minds because brain matter is matter and memories are molecules.