Pre-New 52 (1955-2011)
J’onn J’onzz first appeared at the dawn of the Silver Age, when he found himself instantly teleported to Earth from his home planet Mars in a science experiment gone wrong, conducted by the eccentric Dr. Saul Erdel. By creating a special ray with which to communicate with other worlds, Erdel accidentally brought J’onn to Earth. When he first appeared in Erdel’s observatory home, J’onn communicated to Erdel telepathically, explaining who he was and where he came from. Sadly, the shock of transporting an alien from Mars to Earth seemingly killed Dr. Erdel, leaving J’onzz without a way of returning home.
Realizing that his Martian abilities made him far more powerful than ordinary humans, J’onzz decided to fight crime on his newly adopted planet. He used his shape-shifting ability to assume the alias of John Jones, a hard-boiled detective working out of Middletown, Colorado. Eventually J’onzz changed his heroic name to the Martian Manhunter, after the term often used to describe police officers.
Not long after going public as a green, Martian hero, J’onzz helped save the Earth from an alien invasion along with several other heroes. With his new colleagues, he became a founding member of the Justice League of America. In many ways, the JLA became J’onzz’s new family, replacing the one he’d lost on his dead homeworld. After many years a group of Martian survivors contacted J’onzz, and convinced him to leave the Earth and help them build a civilization on New Mars.
Years later, after returning to Earth and leading a different version of the Justice League, J’onzz found out the truth about his origins. He learned that that Dr. Erdel had not died years before, and that the story of his arrival on Earth as he remembered it was a fabrication. When he first came to Earth, he had actually looked far less humanoid, and the more human form he adapted was because of the physiological trauma he endured—his own mind’s attempts to block out the extinction of his race. (The appearance most people recognize as the Martian Manhunter was based upon Dr. Erdel’s idea of what a Martian should look like based on pulp science fiction stories.) He also learned that he was not only displaced from Mars due to distance, but also time, as the plague that had wiped out his planet, including his wife and child, had actually occurred thousands of years prior.
J’onzz learned that he was born millennia ago, and that the name J’onn J’onzz means “Light to the Light.” He also discovered he had a twin brother who was born a mutant—without the natural Martian ability of telepathy—named Ma’alefa’ak, whose name means “Darkness in the Heart.” J’onzz had become a police officer and married a woman named M’yri’ah, and had a daughter named K’yhm. J’onzz’s brother, however, took the opposite path in life.
Feeling like an outcast due to his lack of mental powers, Ma’alefa’ak caused the genocide of his own race by creating a contagious virus. The virus reacted to telepathic energy and was transmitted from one Martian to another whenever they used their psionic powers. The plague also responded to the Martians’ innate fear of fire, causing them so much mental anguish that they would literally burst into flame. Because of this virus, almost the entire green Martian race was wiped out. The realization of his true past proved heart-wrenching for J’onzz, but he soldiered on as a hero and a member of the Justice League in spite of this new burden.
New 52 (2011-2016)
In the wake of 2011’s FLASHPOINT event, the DC Universe’s timeline was changed. In this new reality, J’onn J’onzz’s origins were altered. His time on Mars was now a million years ago, making him one of the most ancient beings on Earth. When still a young man, he and several other young Martians were recruited for a government experiment, or so they thought. It turned out that the government agent who recruited them, whose name was Ma’alefa’ak (like J’onzz’s brother in the pre-FLASHPOINT timeline), double-crossed the young recruits, killing all of the subjects except J’onzz. He then used their blood for a magic ritual that gave J’onzz superpowers, hoping to use him as a weapon. When the Martian race died, J’onzz was flung to Earth, where he lived many lives under many identities. In the 21st century he became a Super Hero, adopting the name Martian Manhunter.
J’onn J’onzz’s first appearance in the post-FLASHPOINT universe reintroduced him as a member of the covert Stormwatch organization. It was revealed that although he had briefly joined the Justice League, he was not a founding member, and had left after a very brief period with the team due to their lack of trust in him. When he eventually quit the Stormwatch organization, he used his telepathy to erase the knowledge of his ever having been a member from the team’s minds.
When the United States government decided to form their own League, the Martian Manhunter was asked to become a part of the team. This version of the League did not last long, and when it disbanded, J’onzz was asked to join a new League based out of Canada known as the Justice League United.
Following the events of DC UNIVERSE: REBIRTH #1, it appears that at least some of J’onzz’s pre-FLASHPOINT history has been restored. The Justice League now refers to the Martian Manhunter as a former member, and the glue that holds the team together. After the Source Wall was breached in the aftermath of 2017’s DARK NIGHTS: METAL, leading to changes in the Multiverse, the Martian Manhunter was asked to become leader of the League, organizing a powerful lineup of the world’s greatest heroes.