In the comics, the Green Lantern is a member of the Green Lantern Corps. The Green Lantern (this incarnation being Hal Jordan) uses his power ring to fly or generate hard light constructs out of his imagination, such as various weapons or defensive shields. He is voiced by Dermot Mulroney.

Green Lantern first appears (In a speaking Roll) in the Episode ' Ring Toss ' In which Green Lantern seeks out Batman's help in locating renegade Green Lantern Sinestro, but when the villain comes to Earth, the Penguin ends up with the hero's power ring, which Batman gets to briefly use before it runs out of power right as he is about to fight Sinestro, but to keep from falling from the clouds he uses it's remaining juice to crash into an abandoned building and throw the ring to Hal Jordan, just as he gets captured.

Info from Wikipedia and Myself