The original Firestorm was distinguished by his integrated dual identity. High school student Ronnie Raymond and Nobel Prize-winning physicist Martin Stein were caught in a nuclear accident that allowed them to fuse into the "nuclear man" Firestorm. Due to Stein's being unconscious during the accident, Raymond was prominently in command of the Firestorm form with Stein a voice of reason inside his mind. Banter between the two was a hallmark of their adventures.
After the accident that created him, Firestorm took to defending New York from such threats as Multiplex (created in the same nuclear accident that produced Firestorm) and Killer Frost. Their adventures began with the teenaged Raymond adjusting to his newfound role and later delved into the issue of the nuclear arms race and Firestorm’s role as an "elemental." Upon graduation from high school, Raymond entered college in Pittsburgh, where Stein had been hired as a professor.Firestorm's list of enemies included such generally forgotten foes as the Hyena, Zuggernaut, Typhoon, Silver Deer and Black Bison. One Firestorm enemy, Plastique, would later play a major role in Captain Atom's life; she later reformed and married Atom. He also fought Killer Frost, who was forced by the Psycho-Pirate to fall in love with him during the Crisis.
After the Crisis, Firestorm was pitted against the world, as the hero, acting on a suggestion from a terminally ill Prof. Stein, demanded the United States and the Soviet Union destroy all of their nuclear weapons. After tussles with the Justice League and most of his enemies, Firestorm faced off against a Russian nuclear man named Pozhar in the Nevada desert, where they had an atomic bomb dropped on them. When the smoke cleared, a new Firestorm was created who was made up of Raymond and the Russian, Mikhail Arkadin (the Russian superhero Pozhar), but controlled by the disembodied amnesiac mind of Prof. Stein.
The Raymond/Arkadin Firestom proved to be a transitional phase, as in 1989, it was revealed that Firestorm was a "Fire Elemental". Firestorm now became something of an environmental crusader, formed from Raymond, Arkadin, and a Soviet clone of the previous Firestorm, but with a new mind. Prof. Stein, no longer part of the composite at all, continued to play a role, but the focus was on this radically different character. It was during this phase that Firestorm met and befriended Shango and the Orishas, the elemental gods of Africa. He also met their chief deity and Shango's older brother Obatala, Lord of the White Cloth. This was also the situation in which the Shadowstorm entity first appeared.
Stein soon learned that he was destined to be the true fire elemental and would have been were it not for Ronnie Raymond also being there by circumstance. Raymond and Arkadin were returned to their old lives, and Stein, now Firestorm, was accidentally exiled to deep space in the process of saving the Earth. He thereafter spent many years traveling through space as a wanderer, returning to earth on only two occasions: the War of the Gods, and again in Extreme Justice, where Stein cured Raymond of his leukemia and allowed Raymond to retain the original Firestorm persona on his own. After this Ronnie continued to be Firestorm on his own in Earth, but lacking the wise advices of Stein.
After the Justice League of America had traveled 3,000 years into the past to search for a missing Aquaman, Batman puts together a new Justice League to be Earth's protectors while the JLA is gone. Firestorm is among the nine heroes chosen by Batman to be members in this new Justice League. After the Justice League of America returns to the present, the new Justice League disbands. However, several members of the new Justice League, including Firestorm, opt to join the JLA. While a member of the JLA, Raymond acts as a junior member and is constantly cautious of upsetting his teammates and making mistakes in the field; he states vocally a few times that he is afraid of losing his position. While in the League, Ronnie developed a close friendship with Manitou Dawn while he was attempting to teach her the English language.
Subsequently, Raymond was killed during the Identity Crisis. It was revealed that during a battle with a villain called the Shadow Thief, Raymond was impaled by the Shining Knight's sword, which the Shadow Thief had stolen. The magical sword ruptured the nuclear man's containment field, resulting in Firestorm's body exploding and his residual essence funneling into the body of Jason Rusch, the new host of the Firestorm Matrix. His name was featured posthumously on Rip Hunter's chalkboard in the statement "Ronnie Raymond + X = Firestorm".
During the Blackest Night, Ronnie Raymond is called by a black power ring to join the Black Lantern Corps. In the following moments, his reanimated corpse is seen confronting Barry Allen and Hal Jordan alongside Hawkman, Hawkgirl, Elongated Man, Sue Dibny, and J'onn J'onzz. He then attacks Jason Rusch (the current Firestorm), and absorbs him into his own version of the Firestorm matrix. Then, using Jason's unique abilities, turns Gehenna into table salt, simultaneously ripping her heart out with a smile. He uses the Firestorm Matrix to absorb Jason's anger over Gehenna's death, providing the Black Lanterns with even more emotional energies. Then, he goes on to attack Barry Allen and co. at the Justice League satellite. Jason then briefly asserts himself, allowing the heroes to escape. Regaining control, Ronnie proceeds to absorb Jason's willpower. Like other Black Lanterns, the undead Firestorm mimics the personality of Ronnie Raymond, often wisecracking and exhibiting other stereotypical teenage behavior. In the final battle against Nekron, Ronnie is restored to life alongside Jason, the two separating from Firestorm. Ronnie is confused, asking Atom where Professor Stein is while Jason is upset with Ronnie killing Gehenna. Ronnie, however, apparently has no memory of doing so.
During the Brightest Day, Ronnie, still clad in casual clothing from a wild party the night before, arrives at Jason's apartment with Professor Stein and Ray Palmer to attend Gehenna's funeral. Stein and Palmer discuss Ronnie's return and how he no longer remembers anything since his death at the hands of Shadow Thief. While the two talk about the paperwork needed to have Raymond's legal status as "dead" reversed, Ronnie approaches Jason and offers an apology about Gehenna's murder. Jason refuses to accept it, telling Ronnie that he forced him into being an accomplice to the death of his girlfriend, and that he probably doesn't even remember her name. When Ronnie is actually unable to remember Gehenna's name, Jason angrily lashes out and punches him in the face. This causes the two young men to merge into Firestorm, and they begin arguing inside the Matrix while Palmer transforms into his Atom persona in order to help them separate.
Palmer manages to separate Jason and Ronnie, but not before the Firestorm matrix causes a huge explosion, transmutating everything in the Professor's laboratory into table salt. While recovering in the hospital, Stein explains to Ronnie that it seems to be very dangerous to fuse into Firestorm again. Also, it is revealed that Ronnie, after quickly leaving the hospital and being threatened by Jason's father to stay away from Jason, lied to everyone, as he seems to perfectly remember murdering Gehenna as a Black Lantern.
Worse yet, some time after the forceful separation, he lies sleeping in preparation of a party, when a previously heard voice prods him awake - a monstrous construct of Gehenna, made totally of salt, which proceeds to throttle and choke him, taunting him to remember her name; while she is interrupted before killing him, Ronnie is left covered in salt. Not too long after, he is lying, recovering from a massive binge, when Jason again forces the merge to help several construction workers endangered when the girders at the site are transmuted without warning to bubble gum. This time, they again hear the mysterious voice taunting them, and Ronnie accepts he remembers killing Gehenna, and they realize something else is lurking from within the Firestorm Matrix.
As Firestorm, Ronnie and Jason visit Stein in an attempt to find out what is happening to them. Stein reveals to them that the Black Lantern Firestorm still exists in the Firestorm Matrix. Firestorm is then told by the Entity that they must learn from each other and defeat the Black Lantern Firestorm, before he destroys the Entity. Somehow, Jason and Ronnie trade places.
After running a test to deduce the new abilities of Firestorm, Professor Stein reveals the origin of the Firestorm Matrix. Stein believes that during the initial experiment he was able to capture the spark that preceded the Big Bang that created our universe. Thereby making the matrix a trigger for a new big bang, if the boys continue to experience emotional imbalance they increase the likelihood of triggering a new big bang. Stein tells Ronnie and Jason that together they are the most dangerous being in the universe. After explaining this to the boys, the voice inside them speaks again. Declaring that it is not the matrix, a pair of black hands reaches out from inside Firestorm. Forcibly separating Jason and Ronnie, Black Lantern Firestorm stands between them, separate from both Ronnie and Jason and apparently calling itself "Deathstorm". Also of note is that Deathstorm does not appear to be wearing a black ring.
Deathstorm reveals its plan to Stein, stating that it intends to create enough emotional instability between Ronnie and Jason that the Matrix will trigger another Big Bang thereby fulfilling the Black Lantern Corps primary objective: the destruction of all life in the universe. In order to help accomplish this goal, Deathstorm absorbs Stein's mind in order to use his knowledge of Ronnie against him; then, to torture Jason, Deathstorm brings his father, Alvin Rusch, to the lab and absorbs him as well. Taking flight Deathstorm beckons Ronnie and Jason (who by now have merged into Firestorm) to follow it. Deathstorm leads them to Silver City, New Mexico and the resting place of the White Lantern Power Battery. Deathstorm tries to lift the battery but is unable to until he infects it with black energy, after which he is able to lift it with ease. After he threatens to destroy the White Lantern Battery and therefore prevent Ronnie and Jason to truly live, a voice beckons him not to. The voice, apparently the one who is collecting all the emotional entities, commands him to bring the Central Power White Lantern Battery to the voice as well as an army, at which point Deathstorm brings back the Black Lantern versions of Professor Zoom, Maxwell Lord, Hawk, Jade, Captain Boomerang, Martian Manhunter, Aquaman, Hawkman, Hawkgirl, Deadman and Osiris.
Deathstorm and the Black Lanterns teleport to an unknown location, Firestorm, Jason and Ronnie ultimately seek the help from the Justice League. Firestorm arrives at the Hall of Justice asking for help. Firestorm is placed in a containment chamber while the League search for a way to stabilize the energy. However, an internal argument between Ronnie and Jason ignites the spark, apparently resulting in the destruction of the universe. Ronnie and Jason quickly notice, after defeating an hive of Shadow Demons, that the universe was not destroyed as they thought but they were actually transported to the Anti-Matter Universe. There they are contacted by the Entity who reveals to them that since Boston Brand has not yet found the one who will take the Entity's place, it is Firestorm mission to protect the Entity. Meanwhile, Deathstorm and the Black Lanterns are seen on Qward delivering the White Battery to someone. That someone is revealed to be the Anti-Monitor, who seeks to harvest the life energy within the Lantern to grow stronger. Firestorm takes the White Lantern and attempts to fight the Anti-Monitor, but is defeated. Deathstorm then brings Professor Stein out of his Matrix to taunt the two with. Deathstorm then attempts to turn Ronnie to salt, but the Professor takes the brunt of the attack. Angered, Ronnie decides to truly work together with Jason to avenge the Professor. The Entity then declares that Ronnie has accomplished his mission, returning life to him in a burst of white energy that obliterates the Black Lanterns, returns Jason's father to his home, and deposits Firestorm in the Star City forest. Ronnie angrily attempts to make the Entity resurrect the Professor, but is refused. Deadman then arrives, demanding that he be given the White Lantern.
When the "Dark Avatar", made his presence known, Firestorm is made part of the Elementals. Ronnie Raymond was then transformed by the Entity to become the element of fire and protects the Star City Forest from the "Dark Avatar" which appears to be the Black Lantern version of the Swamp Thing. The Elementals are then fused with the body of Alec Holland in order for him to be transformed by the Entity into the new Swamp Thing and battle against the Dark Avatar. After the Dark Avatar is defeated, Swamp Thing brings back Firestorm to normal. Afterward, it is revealed Ronnie and Jason must find a way to contain their Firestorm matrix from the explosion in less than ninety days.