History: Joseph Ledger is a native of the alternate Earth on which the organization of superhuman champions known as the Squadron Supreme arose. Ledger became an astronaut for the Notional Aeronautics and Space Administration (NASA).

While on a mission in outer space, Ledger encountered a disabled alien spacecraft and rescued its sole occupant, a member of the Skrull race, bringing him back to Earth with him. In gratitude, the Skrull presented Ledger with a crystal that Ledger called the power prism. Using the power prism, which granted him great powers, Ledger became the masked costumed champion known as Doctor Spectrum. As Doctor Spectrum, Ledger had a highly successful career as a crimefighter, battling such menaces as Quagmire. Eventually, Doctor Spectrum and the Skrull he had befriended (who become a crimefighter on Earth known simply as "the Skrull") became founding members of the Squadron Supreme. Doctor Spectrum became a close friend of two other Squadron members, the Golden Archer and the Whizzer.

The otherdimensional being called the Grandmaster and the Squadron's foe the Scarlet Centurion held a game in which they pitted the Squadron and a criminal team called the Institute of Evil against each other. The Squadron triumphed, but as a result of this experience, the Grandmaster later created counterparts to certain Squadron members on the Earth of his native dimension. He presented Dr. Kinji Obatu with a "power prism" that was of an entirely different nature than Ledgers (and which, in fact, was sentient) but which granted Obatu similar powers. Thus Obatu became a criminal Doctor Spectrum on his own Earth. This power prism subsequently fell into other hands, transforming other people into counterparts to the original Doctor Spectrum.

The original Doctor Spectrum and all of the Squadron Supreme members active in the team at the time except for Hyperion fell under the psychic domination of the otherdimensional being known as the Overmind, who served the entity call Null the Living Darkness. The Overmind employed the Squadron members in conquering the entire Earth. The Squadron members were freed from the Overmind’s control and with the aid of superhuman champions from another Earth defeated the Overmind and Null. However, the Squadrons Earth had been left in chaos as a result of the Overmind's takeover.

The Squadron resolved to take temporary control of the United States in order to implement their "Utopia Program," whereby they intended to eliminate all the major problems besetting their nation, such as crime and hunger. Horrified by this assumption of absolute power, one of the founding members of the Squadron, Nighthawk, resigned from the organization. When the Squadron took control of the nation, all of its members, including Doctor Spectrum, publicly revealed their true identities as a gesture of good faith. Nighthawk secretly set about planning the overthrow of the Squadron's rule.

The parents of the Squadron's youngest member, Nuke, died as a result of cancer due to long term exposure to the radiation that Nuke himself continually gave off. Nuke went mad from grief and stopped participating in Squadron activities. The Squadron assigned Doctor Spectrum to find Nuke, and Spectrum succeeded in doing so, only to learn that the insane Nuke now intended to kill the Squadron's scientific genius, Tom Thumb, who had been unable to cure Nukes parents. Doctor Spectrum battled Nuke in an attempt to stop him, finally trapping him within an energy bubble created by his power prism. In trying to get free, Nuke unleashed energy blasts that consumed all the oxygen within the energy bubble and thus suffocated. Guilt-ridden over Nuke's death, Doctor Spectrum resolved not to use his powers in combat again. He succeeded in keeping this resolution for the rest of the period of the Squadron's rule, breaking it only when extreme circumstances required him to do so.

Tom Thumb invented a behavior modification device with which the minds of other human beings could be programmed to operate along certain lines. The Squadron used this machine to program the minds of convicted prisoners so that they would no longer engage in criminal activities. Among those subjected to the machine were the members of the Institute of Evil, who were then inducted into the Squadron. One of the former Institute members, Foxfire, became strongly attracted to Doctor Spectrum. Doctor Spectrum's friend, the Golden Archer, however, was expelled from the Squadron after it was discovered that he had used the device to brainwash his fellow Squadron member Lady Lark.

Nighthawk secretly organized a team of costumed agents whom he called his Redeemers in order to oppose the Squadron. Among the Redeemers was the Golden Archer, who now opposed the Squadron's use of brainwashing and other violations of democratic rights, and who had renamed himself the Black Archer. Nighthawk's ally, Master Menace, discovered a means of undoing the effects of Tom Thumb's behavior modification machine, and used it to undo the brainwashing of the former institute members, including Foxfire, who all then joined the Redeemers. However, Foxfire, who had fallen in love with Doctor Spectrum, was uncertain as to whether she was making the right choice by allying herself with Nighthawk against the Squadron.

Nighthawk's Redeemers battled and finally overcame the Squadron at the Squadron's own headquarters, Squadron City. During the battle Doctor Spectrum found himself in opposition to the Black Archer, whom he recognized as his old friend. The Archer aimed an arrow at Spectrum, who hesitated to use his power prism against him, remembering what had happened to Nuke. Thus Spectrum was unable to stop the Archer from shooting the arrow, which shattered the power prism, whose fragments became embedded in Spectrums body. Hoping to prove she was really loyal to the Squadron. Foxfire used her superhuman powers to murder Nighthawk. Another member of the Redeemers, the Mink, who was in love with Nighthawk, then mortally wounded Foxfire in retaliation. Enraged by Foxfire's death, Spectrum wanted to strike out against the Mink, and found, to his surprise, that a beam of concussive energy emerged from his body and struck the Mink down. The powers that formerly existed within the power prism now resided within Spectrum's own body. Spectrum's body and costume had also turned pure white.

Doctor Spectrum and the surviving Squadron members surrendered to the Redeemers and turned control of the United States government back over to the American people's elected representatives. What has happened subsequently to Doctor Spectrum and the other Squadron members has yet to be revealed.

Height: 6 ft.
Weight: 190 lbs.
Eyes: Brown
Hair: Formerly black, now white

Strength Level: Doctor Spectrum possesses the normal human strength of a man of his age, height, and build who engages in moderate regular exercise.

Known Superhuman Powers: Previously, Doctor Spectrum possessed no actual superhuman powers. However, he owned an alien "power prism" of unknown origin which was given to him by a member of the Skrull race

This crystalline object responded to Doctor Spectrum's thoughts and could perform various feats at his mental command. Hence, Doctor Spectrum could command it to levitate him and project him through the air at great speed, thus enabling him to fly. At Doctor Spectrum's mental command, the prism would emit powerful concussive energy blasts, light, heat, and other forms of radiation. At Doctor Spectrum's mental directions, the prism could also form objects composed of an unknown form of energy that would function according to Doctor Spectrum's will. These objects could become solid, as if they were made of matter, if Doctor Spectrum so willed.

It is not known whether or not the power prism would respond to the will of anyone other than Doctor Spectrum. It is known that Doctor Spectrum could mentally control the prism even if he was not physically in contact with it, but it is not known if there was a limit to the distance over which Spectrum could be separated from the prism and yet still retain control over it.

Unlike the power prism used by Dr. Knit Obatu, the Doctor Spectrum created by Grandmaster, the original Doctor Spectrum's power prism is not sentient. Apparently, the original Doctor Spectrum’s power prism was not made from a living being, as was Obatu's.

When the Black Archer's arrow shattered the original Doctor Spectrum's power prism, the fragments of the prism embedded themselves in Spectrum's body. As a result Spectrum's body now possesses the powers of the prism, and he can mentally direct the prism's energies to emerge from his body to perform according to his will. His body is now chalk white in color. It takes on bright colors when projecting energy.

The limits to Doctor Spectrum's s superhuman powers are unknown. However, it is known that the amount of power he can generate is dependant upon the intensity of his own will power.