Name: Hal Jordan
Alias: Green Lantern II, The Spectre, Parallax
First Appearance: Showcase #22 (October, 1959)
Modus Operandi: current: Interstellar lawman, formerly: agent of God's Vengence, formerly: universe destroying madman, formerly: interstellar lawman, formerly: Air Force pilot
Powers/Equipment: Power ring fuelled by willpower, able to perform any task/action provided that Jordan has sufficient willpower/imagination.
Backstory: Test pilot Hal Jordan's life was changed forever when a dying alien chose him as his replacement in an interglactic police force known as the Green Lantern Corps.
Jordan used his new-found abilities to fight crime and evil in his native Coast City, all the while hiding his identity as "Green Lantern" from his loved ones, including his boss/girlfriend Carol Ferris.
Jordan went on to become a founding member of the Justice League, becoming fast (and eventually, best) friends with the quickly recruited Green Arrow. After the two had an arguement over Jordan's niave acceptance of authority in all its forms, the two travelled the country together, righting wrongs and learning about tolerance.
Later, after Superman's death, the villainous Mongul destroyed Jordan's home, Coast City. Driven mad by grief and angry at the Guardians of the universe for denying him the power to restore the city, Jordan went on a rampage, destroying the Green Lantern Corps and stealing their power for himself.
Using his vast power, Jordan planned to remake the universe to his wishes, namely restoring Coast City and forcing law and order on the populace. It was only through the intervention of his best friend, Oliver Queen, that his plan was stopped. Ollie was forced to kill his friend rather than let him carry out his plan, an action that haunted him for years afterward.
Jordan turned out not to be dead (very complicated) and feeling guilty for his actions, sacrificed himself to restart Earth's sun. After his death, he accepted the offer to become the new Spectre, carry out God's wishes and bringing evildoers to justice.
To further complicate matters, Jordan was recently restored to life and regained the mantle of the Green Lantern of Earth. Green Arrow was crucial to his rebirth, having kept a copy of Jordan's ring safe for years and protecting Jordan's replacement Kyle Raynor from a rampaging Sinestro.
The two have since rekindled their friendship, and Jordan has retaken his place on the Justice League along side Ollie's former sidekick, Roy Harper.