Brilliant scientist John Starr was working as assistant to Dr. Elijah Carruthers when Carruthers created an artificial humanoid called Cosmo. However, Cosmo proved to be imperfect, so Carruthers destroyed him. Soon afterwards, the Doctor disappeared and was assumed dead.
Starr then turned to crime, but was caught by the police and sent to prison. While inside, he was allowed to work in a special automated laboratory that was regarded as being escape proof. There, he worked on a discovery involving the control of time by harnessing the speed of light - a univeral constant - and this enabled him to build an hourglass that sent him back in time to before the prison was built; and he escaped by simply walking away.
Now calling himself the "Modern Monte Cristo", he set out to convince the public he had been railroaded into prison. He learned the secret identities of Batman and Green Lantern by peering through time, then used this knowledge to capture Batman, take his place, and trick Green Lantern ( Hal Jordan) into using his power ring on him so that he could absorb some of the ring's power and add it to his own abilities.
Disguised as Batman, Starr embarked upon a series of super powered crimes. Green Lantern found the real Batman and the pair went after the imposter, who revelaed himself as the Time Commander. Using the power from the stolen ring, he overcame the heroes and took them to his hideout behind a clock face on a billboard and trapped them in time.
Green Lantern and Batman communicated via the power ring, and set up a siren at the precise pitch to shatter Starr's hourglass. Starr's time tampering to force the authorities to clear his name were negated and the two heroes returned to the present. Green Lantern wiped the memory of their secret identities from Starr's mind and returned him to prison.
Starr did escape again, and having decoyed Batman into leaving town on a fake mission, took his place and got Green Lantern to help him escape from a fake trap. He then used the stolen ring power to reach into the past and revive Cosmo, who went on a rampage, looking to kill Dr. Carruthers.
Batman discovered that Carruthers was not dead, but in a nursing home, suffering from amnesia, brought on by overwork and stress. When his memory returned, he was able to destroy Cosmo again, while Batman and Green Lantern captured the Time Commander.
Time Commander would appear in an hourglass and berate Waverider for the failed promise of making himself and Chronos Time Masters for joining his fight. He is quickly turned to sand by Skeets, secretly Mr. Mind, who then also dispatches Waverider.
A second Time Commander, Sterling Fry, was being mentored by Starr. He kidnaps Liberty Belle and steals Hourman's hourglass. He releases the tachyon particles from the hourglass and disappears. It is unknown what affect this may have on this new Time Commander.