Jean Loring began her career as a lawyer about the same time that physicist Ray Palmer first began adventuring as the Atom. She did not know that her fiancé was really the Atom for many years, despite the fact that she had aided the Atom on several of his adventures. Jean eventually discovered Ray's secret identity and the two were married. The Palmers' marriage was rife with difficulty, due primarily to Ray's double-life as a super-hero. The intensity between them strained when the Atom began devoting large portions of his time to the Justice League of America. Ultimately, the two could not reconcile their lives together and they divorced. Following their separation, Ray abandoned life in Ivy Town to live in a miniature jungle environment with a colony of six-inch humanoids known as the Morlaidhian, under the rule of Princess Laethwen. With Ray gone from her life, Jean remarried to a fellow attorney named Paul Hoben.
Jean and Paul left Ivy Town and opened up a small firm in Calvin City. After practicing for several years, they eventually returned to Ivy Town, where Jean became senior partner at Grabemann, Loring and Ross.
Recently Jean suffered a mental breakdown and was desperate to get back together with Ray Palmer. She shrunk herself using one of Palmer's old costumes and tried to give Sue Dibny a minor stroke. She hoped that the incident would cause the heroes to become closer to their loved ones and in the process drive Palmer back to her. Unfortunately, Jean killed Sue.  She incinerated her body to cover it up, starting a disastrous chain of events.
She then faked an attempt on her life, and set up Captain Boomerang to take the fall. Boomerang was sent to attack Timothy Drake's father while an anonymous tip alerted Drake. However, both men died. Palmer did return to his ex-wife, but Jean revealed information about the murders in passing, leaving her exposed as the killer.
Incarcerated in Arkham Asylum, Jean was abused by other prisoners. She found a black diamond in her cell one day and became the new host for Eclipso. As Eclipso, she convinced the Spectre to massacre magical beings. During a battle with other magic users, Jean was sent orbiting around the sun.
A short time later, Ralph Dibny—accompanied by the helmet of Doctor Fate—approached the Spectre as part of his quest to restore his wife Sue to life, promising to fulfil any bargain demanded of him in order to accomplish this. The Spectre, desiring revenge on Eclipso but rendered incapable of taking it (owing to his lack of a host), ordered Dibny to punish Eclipso in return for his wife's life; Dibny, intending to punish his wife's murderer and temporarily granted the power of the Spectre, took Eclipso back to the point at which she (as Jean Loring) murdered Sue and, restoring Jean's sanity, intended to trap her in a permanent time loop, forcing her to watch herself murder Sue Dibny over and over for all eternity. Her sanity restored, a terrified Loring tearfully begged for forgiveness, screaming that she loved Sue and that she was crazy when she killed her. Dibny, affected by her pleas, found himself incapable of such ruthlessness and refused to complete his pact with the Spectre, returning Eclipso to her orbit around the sun, and moving on to find another being with whom he could accomplish his goals. 
Eclipso later returns to Earth, kidnapping a baby with huge raw magical abilities to corrupt into a new host for herself. The combined efforts of Blue Beetle and Traci Thirteen foiled her plans, steering her attentions on Mary Marvel herself. Failing in getting a new host for herself, Eclipso, still bonded with Jean Loring, finds in Mary Marvel a new companion, and instrument of power. Feeding to the young girl mistrust and lies, Jean manages to sway Mary from the side of the heroes, corrupting the young girl into her follower. Mary Marvel however rebels, and refusing to be given to Darkseid as a concubine, strips Eclipso of her black diamond and blast herself unconscious and powerless in space, fleeing away. Eclipso retrieves the diamond and attempts to kill Mary, only to find that she is too strong for her. During the battle, Mary calls down the magic lightning bolt, removing Eclipso's power from Jean, who sinks into the ocean.
Jean drowned in the sea, but her body was recovered and buried. Several of the heroes had forgiven Jean by this point, and she was considered a member of the hero community once more, a fact which did not sit well with others such as Hawkman.
- Heart of Darkness (formerly)
- Although this character was originally introduced during DC's Earth-One era of publication, their existence following the events of the 1985–86 limited series Crisis on Infinite Earths remains intact. However, some elements of the character's Pre-Crisis history may have been altered or removed for Post-Crisis New Earth continuity, and should be considered apocryphal.
- 173 Appearances of Jean Loring (New Earth)
- 19 Images featuring Jean Loring (New Earth)
- 3 Quotations by or about Jean Loring (New Earth)
- Character Gallery: Jean Loring (New Earth)