The transformation of Jonathan Osterman in Doctor Mahnattan, with scenes from both the graphic novel and the movie

Doctor Jonathan Osterman a.k.a. Doctor Manhattan is a main character in .

Due to an accident involving a nuclear physics experiment, Dr. Osterman was taken outside the physical realm and returned with god-like powers, including superhuman strength, telekinesis, the ability to teleport himself or others over planetary, and interplanetary distances, control over matter at a subatomic level. Furthermore, he perceives the past, present and future as happening simultaneously, but at least believes that he cannot act on that knowledge since his own actions and reactions to chronological events are apparently predetermined.

While his military backers market him as a , he grows increasingly disinterested in human affairs, despite his importance in the Cold War, and is unable to connect with others (especially his love interest Laurie, the second Silk Spectre). Like most characters in Watchmen, Manhattan appears to have a personality disorder, in his case, Schizoid personality disorder which is characterized by reclusiveness and voluntary withdrawal from socializing to the detriment of personal relationships.

Doctor Manhattan was born Jonathan Osterman in 1929. His father was a watchmaker, and Jon planned to follow in his footsteps. When the US drops the atomic bomb on Hiroshima, Jon is sixteen. His father, confronted with the undeniable facts of the theory of relativity, declares his profession outdated and throws his son's watch-making parts out the windows, urging him to instead pursue a career studying nuclear physics. The incident represents the turning point in Jon's potential future from watchmaker to nuclear physicist and foreshadows Doctor Manhattan's 'exterior' perception of time as predetermined and all things within it as so determined, including Doctor Manhattan's own reactions and emotions. Jon Osterman attends Princeton University from 1948-58 and graduates with a Ph.D. in atomic physics. In early 1959, he moves to a research base at Gila Flats, where experiments are being performed concerning the 'intrinsic fields' of physical objects which, if tampered with, result in their disintegration. Here he meets Janey Slater, a fellow researcher; they eventually become lovers. During a trip to New Jersey in July 1959, Jon and Janey visit an amusement park. Janey's watchband breaks, and the watch is damaged when a fat man steps on it. Jon decides that he can repair the watch, and tells Janey so. That night they sleep together.

One month later, on August 20, 1959, shortly after his thirtieth birthday, Jon plans to give Janey the repaired watch, only to discover he has left it in his lab coat which is inside the intrinsic field experiment test chamber. While Jon is inside the test chamber retrieving his coat the door closes, automatically locking as a safety feature. Unable to open the door or override the countdown, Osterman's colleagues - save for Janey, who cannot bear to see the last moment and flees the room - can only watch, horrified, as the countdown for the current experiment shortly reaches zero, and Jon has his 'intrinsic field' removed. Bathed in the radiant light, he is torn to pieces from the force of the generator, instantly vaporized and officially declared dead.

The following months see a series of strange events and apparitions at the research base, leading residents to speculate the area is now haunted. It becomes plain that Jon has been progressively reforming himself during this time. This progression being indicated by a series of partial bodily reappearances: first as a disembodied nervous system, ncludingi the brain and eyes; then as a circulatory system; then a screaming partially muscled skeleton. Each time, the appearance only lasts for a few seconds. Jon fully reappears on November 22 as a tall, hairless, naked, blue-skinned figure.

After his transformation, Jon begins to experience time in a non-linear, "quantum" fashion, and it is implied that he is aware of and experiencing all the moments of his life simultaneously. Jon is not omniscient; he remains reliant on his intellect and sensory experience to reach conclusions, but his range of sensory data has been abruptly extended, in proportion to the lessening of his emotional capacities. This often leads him to arrive at conclusions greatly different from those available toormal n humans. However, during the course of Watchmen he displays powerful emotion several times. His apparent lack of sentiment is more a matter of radically altered priorities, owing to a colossal, unbridgeable gap of perception between Jon and the rest of humanity.

He subscribes to a deterministic view of events. During the period in which Doctor Manhattan is a crime-fighter (at the behest of the government), he states that the morality of such activities escapes him. From his radically altered perspective, almost all human concerns appear pointless and without obvious merit.

Jon gradually becomes a pawn of the United States government, though the means by which his loyalty is secured are never revealed; he is given the code name 'Doctor Manhattan', a reference to the Manhattan Project that, it is hoped, will defeat America's enemies. He is also provided with a costume which he grudgingly accepts, though he refuses to accept the icon design which is provided for him (this being a stylized orbital model of the atom). Instead, Jon chooses as his emblem a representation of a hydrogen atom, whose simplicity he declares to be something that kindles his respect; accordingly, he painlessly burns the mark into his forehead. This preference for material mechanisms marks the beginning of Jon's declining humanity, which is progressively mirrored by his gradual shedding of the uniform - by the end of the 1970s, he refuses to wear anything at all except for mandatory public appearances.

During the first meeting of theCrimebusters superhero group, Laurie Juspeczyk, the second Silk Spectre, catches his eye. His relationship with Janey Slater ends acrimoniously shortly after, and he begins dating Laurie.

During the execution of Adrian Veidt's plot to save the world, Manhattan is accused of giving cancer to those exposed to him over long periods of time. It emerges that this is untrue, for it is rather a careful fabrication of Veidt's, but this revelation is not quick enough to prevent Manhattan from exiling himself to Mars, where he spends much of the action of Watchmen. Eventually, he brings Laurie (who, in the meantime, has taken Dan Dreiberg/ II as a new lover) to Mars, where they argue over the fate of the human race.

He leaves Earth for Mars when he is accused of causing cancer in his close associates over the years. However, this was a frame arranged by Veidt to induce Osterman to leave, to remove his interference in his scheme to save the world. Eventually, he brings Laurie to Mars to discuss why he should do anything to aid humanity, an argument Laurie inadvertently wins when she goes through her life and realizes to her shock that her father is the , a man whom she despised for sexually assaulting her mother. From that revelation, Doctor Manhattan is amazed by the improbable chances that occurred to result in the birth of Laurie, which he sees as a stunning "thermodynamic miracle." By extension, this miracle can apply to any living thing on Earth, and so Doctor Manhattan decides to return to Earth to protect humanity rather than disregarding it as insignificant.

Although they return too late to stop Veidt's plan, they teleport to Antarctica to confront him. Veidt hinders Doctor Manhattan with a tachyon generator that interferes with Doctor Manhattan's ability to see the future, and then disintegrates him by subtracting his intrinsic field. To Veidt's surprise, Doctor Manhattan restores himself much more quickly this time, but when Veidt reveals that his scheme, in which he used his alien monster to kill half of New York City, appears to have averted the looming nuclear war by frightening the world's governments into cooperation, Doctor Manhattan realizes that to expose the scheme would be too dangerous for all life on Earth. Doctor Manhattan and the other superheroes except for agree to keep quiet to preserve Veidt's results. Rorschach leaves on his own and is murdered by Doctor Manhattan to prevent him from ever telling the truth. Manhattan does so reluctantly, at Rorschach's own insistence, who asserts that his death is the only thing that will ensure his silence. Doctor Manhattan does not mention Rorschach's death when talking to Veidt not long after, instead telling Veidt he "does not think Rorschach will reach civilization".

At the end of Watchmen, Doctor Manhattan decides to depart Earth again, but he might return one day. Veidt is surprised by his decision, pointing out the apparent contradiction with Doctor Manhattan's renewed interest in human life, to which Doctor Manhattan suggests that he may "create some [human life]" in another galaxy. When Veidt asks if his plan worked out in the end, Jon Osterman smiles and enigmatically replies that "nothing ever ends."