- Mortal Kombat II: "His real name is Maj. Jackson Briggs, leader of a top US special forces unit. After receiving a distress signal from Lt. Sonya Blade, Jax embarks on a rescue mission. One that leads him into a ghastly world where he believes that Sonya is still alive."
- Mortal Kombat 3: "In failing to convince his superiors of the coming Outworld invasion, Jax covertly prepares for the future battle with Kahn's minions. He outfits both arms with indestructible bionic implants. This is a war Jax is prepared to win."
- Mortal Kombat 4: "When Sonya disappears while tracking the last living member of the Black Dragon, Major Jackson Briggs heads after her. He soon finds that Sonya's mission has led her into a battle with the forces of an evil Elder God. This is a battle they must win or their own world will crumble at the hands of Shinnok."
- Deadly Alliance: "Jax spent most of his time in the heavily fortified underground facilities of the Outerworld Investigation Agency. From an enormous underground chamber, Jax would send his agents to other realms by way of man-made inter-realms portals. Two of his agents, the cyborg ninja Cyrax and the rogue swordsman Kenshi, had been assigned to the realm of Outworld - a domain of strange creatures and maniacal sorcerers. Jax would soon be reminded of just how dangerous a threat to Earth that realm could be. After receiving information from Agent Kenshi about a new threat from Outworld, Jax barely escaped with his life when a traitor destroyed all means for inter-realm travel. The Outerworld Investigation Agency was completely obliterated. But with the help of the Thunder God Raiden, Jax eventually made it to Outworld to deal with the traitor who now serves the Deadly Alliance. Jax swore that he would show no mercy to the one responsible for the destruction. The hunt for Hsu Hao had begun."
- Unchained: "During our assault on the Deadly Alliance, we were overwhelmed by Tarkatan hordes. The last thing I remember seeing was Raiden blasting his way into the main hall. I was later resurrected by Onaga, who controlled my mind and commanded me to enforce his will. My brutality as Onaga's pawn will haunt me forever. If not for Liu Kang, I'd still be under the Dragon King's spell killing the people I've dedicated my life to protect. Now that my soul is unchained, I'm coming for you Onaga. It's payback time."
- Armageddon Bio Kard: "Due to his military successes, Jax has climbed the ranks of the Special Forces Outerworld Investigation Agency. To aid him in the fight against invasion from other realms, he has replaced his own arms with mechanical ones. He was last seen in Outworld hunting for the Red Dragon member, Hsu Hao."
- MK vs DCU: "A decorated soldier and formidable warrior, Jax found that he could enhance his strength and fighting ability through technology. Replacing his arms with cybernetics, he has become a juggernaut in the fight to protect Earthrealm. After Emperor Shao Kahn's invasion, Jax realized that the military was unprepared for threats from other realms. He and his partner, Sonya Blade, formed a division of the Special Forces tasked with monitoring threats not from this world. The Outerworld Investigation Agency will soon face its first crisis."
After a prison break at the Special Forces' detention facility, Jax, who was driving along a highway, received a transmission from his fellow Special Forces operative Gemini detailing the escape and the escapees: No Face, Tasia, Jarek and Tremor. She informed him that they had escaped to a warehouse on the town's south side, likely receiving assistance from an outside source. Jax surmised that source to be Kano, the Black Dragon leader. He received another transmission from one Lieutenant Sanchez, whose squad had arrived at the warehouse. After the transmission was cut off at the source, Jax arrived at the scene to find the squad massacred. For this, he swore he would achieve vengeance against Kano. Using prototype bionic implants on his arms in order to enhance his strength, Jax set out to find his enemy.
Infiltrating into the warehouse, Jax confronted No Face and dispatched him. Proceeding into the sewers, he eliminated Tasia. At this point, Jax contacted Gemini who informed him that the Black Dragon were using a corporate building as a front for their base of operations. At the building, Jax confronted and defeated Jarek, and his investigation led him to the town of the lost city of Sinkiang, where he defeated Tremor and discovered a portal to Outworld which Tremor had been guarding. Surmising that the portal was linked to Kano's plans of global domination, he entered. The portal led to Outworld, and Jax caught up with Kano, who had acquired an artifact called the Eye of Chitian through which he could acquire great power. After an exchange of words, the two fought, and Jax emerged victorious. He used the Eye's power to bring them both back to Earthrealm and brought Kano into custody, only to have the criminal escape at a later date. At this point, Jax ceased using his bionic implants.
Following the end of the Mortal Kombat tournament in which both the wanted Kano and Jax's friend, Lt. Sonya Blade, had entered, Jax came across the Earthrealm warriors, finding Johnny Cage in the waters close to the Special Forces Agency, and took him in for an interrogation on the whereabouts of Sonya. Cage explained the events that took place on the island although Jax didn't believe him until he received a video signal from Sonya, whom was temporarily working with Kano to escape Outworld. As an apology to Cage for not believing his story, he visited him at a commercial shoot where Cage was attacked by Outworld forces. Jax fought against the Shokan, Kintaro, but their fight was interrupted when the Earthrealm warriors arrived to help. After helping Cage fight against the intruders, Jax traveled into Outworld once more to compete in the next tournament along with the Earthrealm warriors in hopes of finding Sonya.
Soon, Jax came to learn of the emperor, Shao Kahn's dark plans for Earthrealm. He was successful in freeing Sonya from the clutches of Shao Kahn and arresting Kano once again, though he eluded capture as soon as they had passed through the portal to Earth. Jax warned his government of the impending danger but would find himself frustrated, however, as not only did Kano escape back into Outworld, but the government did not believe the Major.
Jax began to prepare for war covertly, and once more outfitted his arms with bionic implants. After helping foil Shao Kahn's attempt to permanently claim Earth as his own, Jax became the commanding officer of the Outer World Investigation Agency (OIA). They operated from an underground bunker, and had scouts in various realms, not only exploring and mapping them, but also looking for inter-realm portals that could lead to Earth: these needed to be destroyed.
Sonya went missing once again on a mission to exterminate the last known member of the Black Dragon, Jarek. Soon Jax found that Sonya was led into battle against Shinnok, a fallen Elder God. He briefly assisted Raiden in defeating Shinnok in Edenia. During these events, he and Sonya found the Lin Kuei cyborg, Cyrax, malfunctioning and trapped in a desert. Returning with him to their home base, they reversed the automation process, restored his humanity, and gained a new ally.
Jax also found the Black Dragon member, Jarek, who he threw off a cliff, assuming that it would be the end of him.
Years later, trouble occured again, his agents Kenshi and Cyrax lost in Outworld and the OIA underground facility was nuked into oblivion by the traitor, Hsu Hao. Soon after these events, Raiden summoned the Earthrealm warriors to the abandoned island of Shang Tsung and asked them to travel with him to Outworld to bring down the Deadly Alliance, Jax didn't hesitate. He used this trip as a cover to track down Hsu Hao and, once he caught up with the criminal, killed him by tearing out his artificial heart.
He, like his friends, was eventually found by Onaga and revived as a mindless drone, used to intimidate the survivors of his group before killing them outright.
Sonya sent Jax to lead a team of Special Forces to search for survivors after destroying Sektor's Tekunin Warship, but they vanished and were captured by the Tekunin. His own cybernetic bio scanners sent out mysterious readings before contact is lost, and Sonya feared the possibility of Jax's death.
Later on Jax joined the Forces of Light in the battle of Armageddon, he was able to break Quan Chi's leg in the fight before he was attacked by the emperor Shao Kahn. He, like many other kombatants, died during the battle. His corpse can be seen impaled on a spear in the introduction to Mortal Kombat (2011).
Jax is first heard in Sonya's chapter during the Mortal Kombat side of the story, contacting Sonya and questioning the strange woman in the brig of the Special Forces base. Sonya requests that they rendezvous as soon as possible, and Jax finds her at Raiden's Temple, having just defeated Green Lantern and Captain Marvel but when Sonya suddenly accuses him of being Kano, Jax is confused before being forced to fight the rage driven Sonya, defeating her. Their fight is ended by the arrival of Raiden and Liu Kang, the thunder god demanding an explanation for battling on his temple's grounds.
Jax can't give Raiden a real answer, only knowing Sonya just attacked him, with Sonya herself saying he appeared as Kano to her. Raiden then informs Jax and Sonya of the invaders, as well as the fact that Earthrealm is merging with another realm before pointing out the location of the enemy's satellite. Jax decides to instigate a counterattack, so he and Sonya return to the Special Forces Base to use the portal to infiltrate the satellite.
As Jax prepares the portal, Lex Luthor sneaks up on him and while he admires Jax's portal technology, Jax is overcome by the Kombat Rage and attacks Luthor, knocking him out and locking him up with Catwoman. Jax and Sonya then use the portal to enter the invader's satellite, but are separated. Jax sees a guard escorting Captain Marvel to a cell and knocks the guard out, but his mechanical punches only serve to annoy the Rage afflicted Captain Marvel, though Jax defeats him.
Jax then comes across Wonder Woman, with Sub-Zero held captive by her, and while he tries to shoot her with his Machine Gun, she only deflects the bullets with her bracelets before attacking Jax, consumed with fury from the Rage. Jax defeats her and frees Sub-Zero, who goes to find Raiden. Jax then confronts the returned Green Lantern, once more infected with the Kombat Rage, but he is defeated.
Jax recovers and sometime later heads back to the Special Forces base, where he sees Lex Luthor once more, attempting to create a portal to another realm. Jax battles Luthor again, but is defeated. Jax recovers and contacts the others, informing them that the enemy is heading to Outworld. Jax joins the united Forces of Light and Darkness on the journey to the ruins of the merged Apokolips/Outworld.
Upon Dark Kahn's arrival, Jax like everyone else is overwhelmed by the Kombat Rage before taking part in a final battle against the DC Universe heroes and villains. Jax fights Lex Luthor once again, but is knocked unconscious. He later witnesses the restoration of the realms after Dark Kahn's destruction.
- Mortal Kombat II (Semi-Canonical): "Jax finds Sonya held captive alongside their archenemy Kano. Her only chance of escape is by Jax entering Shao Kahn's contest. With fierce determination, he catches the Outworld warriors off guard and wins the tournament, bringing Shao Kahn's rule to a crashing halt. During the chaos that follows, Jax and Sonya escape through the dimensional gate from which they entered. Kano once again eludes capture but Jax and Sonya know they will cross paths with him in the future."
- Mortal Kombat 3 (Non-Canonical): "The second time Jax battles the forces of Shao Kahn, he comes prepared. Thought to be the strongest man on Earth, he has no problem proving it: First by defeating Kahn's armies, then by defeating the emperor himself. When the world reverts back to normal, Jax and Sonya start the Outer World Investigation Agency. Jax runs the exploratory division which learns to open portals through Science rather than magic. He leads the first expedition into a mysterious new realm."
- Mortal Kombat 4 (Semi-Canonical):
- Sonya: It's over, Jarek! Shinnok is dead, the good guys won! You're coming back with me!
- Jarek: (advancing towards Sonya, who walks backwards) Never, Sonya. I agreed to defeat Shinnok, not turn myself in to the Special Forces! The Black Dragon'll live on!
- (they stop as Sonya stands back-to-back with a cliff)
- Sonya: The Black Dragon died with Kano! You're the last one, Jarek!
- Jarek: NEVER!!! (lunges at Sonya, who dodges, making him plummet into the cliff. Sonya just watches, pulling out her walkie-talkie)
- Sonya: Come in, Maj. Briggs. This is Lt. Sonya Blade. Over-- What? (Jarek has come back up and pulls Sonya's leg, making her fall down the cliff)
- Jax: (over the radio) Sonya! This is Maj. Briggs! Come in! Sonya, this is Jax! Are you there? (Jarek crushes Sonya's walkie-talkie under his foot before laughing and leaving, until...)
- Jax: (holding Jarek in a chokehold) Going somewhere, Jarek?
- Jarek: Jax?! I-I thought you were...
- Jax: Thought I was what? Dead? Like my partner you just tossed off the cliff? (holds Jarek over the cliff by the throat)
- Jarek: I'm-I'm sorry, Jax... Please... Don't drop me... Wait!... I-I promise...
- Jax: Too late, Jarek.
- Jarek: You-you can't drop me! You have to uphold the law! You have to arrest me! Wait-wait! This is brutality! You can't do it!
- Jax: Wrong, Jarek. This is not a brutality. This is a Fatality! (releases Jarek, who falls down)
- Sonya: It's over, Jarek! Shinnok is dead, the good guys won! You're coming back with me!
- Deadly Alliance (Canonical): "Jax had a score to settle with the traitor he knew as Hsu Hao. Now revealed to be a member of the Red Dragon, Hsu Hao had infiltrated the Special Forces Outerworld Investigation Agency and destroyed it with a miniature nuclear weapon. Making good on his promise, Jax eventually caught up with Hsu Hao and ripped the implant from his chest in retribution. Hsu Hao died a most painful death."
- Unchained (Non-Canonical): "The Dragon King had defeated us all, save one: Jax. And though I had absorbed the fighting abilities of those who had aided me, I lacked the raw anger that propelled Jax into battle. Brutally pounding Onaga into submission, Jax finally ended the conflict by embedding a Kamidogu in the would-be ruler's head. Where he summoned so much rage from, I cannot say. I only hope that his anger is finally purged."
- Armageddon (Non-Canonical): "When Jax absorbed the power of Blaze, the cybernetics in his arms grew and permeated his entire body. He was transformed into a full cyborg. He became aware of a controlling neural chip that had been implanted in his brain by Sektor. Enraged, Jax defeated Sektor and claimed leadership of the cyborg ninja clan, the Tekunin. It is unknown if he will ever return to the Special Forces."
- MK vs DCU (Non-Canonical): "Badly injured in the melee with the otherworldly invaders, Jax knew he must enhance his cybernetics to save his own life. He underwent massive anatomical restructuring, replacing most of his body with mechanized, fully armored versions. Jax is now more powerful than ever, but at the cost of his humanity."