Jim is the youngest of the Jordan brothers. At first, magazine reporter Sue Williams thought that Jim and the Green Lantern were one and the same person and wanted to get Jim to reveal his "secret". Not knowing that Green Lantern was actually Jim's older brother Hal, all of Jim's attempts to prove that he wasn't the superhero failed, and Sue remained convinced that it was him. Jim and Sue start dating, and eventually marry in issue #31.
Jim Jordan is Hal's younger brother and appears to be somewhat of a mama's boy discouraging his brothers from fighting and warning Hal to wear his seatbelt when Hal gets in his mother's car. On Hal's 18th birthday he brings Hal a gift that he has kept hidden under his bed. However, Hal has left the family house to enlist in the United States Air Force.
Later, Jim appears outside of a bar Hal has been frequenting in Coast City to warn Hal that their mother is dying of pancreatic cancer. Hal asks to see her but Jim informs him that anything that upsets her could trigger more physical problems. He says that he and Jack (Hal's older brother) refuse to let Hal see her so long as Hal is in the Air Force.
After Hal is discharged from the Air Force he comes to visit his mother in the hospital. Jim tells Hal there was a complication and their mother is dead. He breaks up a fight between Hal & Jack. Later he brings Hal the present he originally intended for his 18th birthday. Hal opens the gift and its a framed photo of Hal & Jim when they were kids.
Later at his mother's graveside Hal and Jim have a heart to heart talk. Hal admits that he's never been a good brother to Jim and wants to tell him something. He then turns into Green Lantern before Jim's bewildered eyes and hands him a flight journal. He says he wants to let Jim into everything thats gone on in his life so he wrote everything down for him.
Jim loses his brother Jack to a supernatural attacker; this is when Hal is carrying the Spectre; the spirit of vengeance.
Jim moves his family to the rebuilt Coast City. It soon comes under attack by the fear-based Yellow Lanterns. Jim and the Coast City show their resistance to the Yellow Lanterns by causing green lights to shine out of their homes.
When Parralax takes over Hal's friend Kyle, it goes after Jim's family. Hal saves them at the last moment.