In 1955, in the back pages of the Batman focused Detective Comics, a new superhero was introduced in a story titled “The Strange Experiment of Dr. Erdel.” Dr. Erdel was a Chicago based astronomer who has constructed a device to communicate with the planet Mars, which Erdel believes is inhabited. The device malfunctions and accidentally teleports a Martian to Earth. Erdel is so shocked by this he has a heart attack and dies leaving the confused Martian alone on this strange new world. His Martian name is J’onn J’onnz and, due to his ability to shape shift, he takes the alias John Jones and fakes credentials to become a police detective in the Windy City. J’onn would keep his Martian identity secret for many years, using his telepathy, flight, and ability to phase through solid matter to foil criminals without them realizing it. But, he could only hide for so long.
J’onn’s big public debut came with the formation of the first Justice League of America. The mind controlling alien Starro attacked the Earth and the greatest of Earth’s heroes came together to stop it (Superman, Batman, Wonder Woman, The Flash, Green Lantern, Aquaman). J’onn joined their side taking a more humanoid form, but keeping his alien nature through his green skin and the symbol of his home planet on his belt. J’onn was to become the most stable member of the League, being a member of every incarnation that followed, except for the current version. During this time J’onn yearned to return to his home world and be reunited with his wife and daughter. Eventually, this wish came true but what he found broke his heart.
It seems that Erdel’s device had not simply transported J’onn to Earth. It had pulled him through a thousand years of time to the present on our planet. J’onn learns that the civilization of Mars had been destroyed in his absence, a few red dust covered ruins remain. He returns to the Earth for good and helps form a new Justice League alongside Aquaman, becoming very attached to his team members which are his makeshift family. The villainous god Darkseid decides to test the mettle of Earth’s heroes around this time and in the aftermath many of the members of the League are killed. J’onn is lost in the world until businessman Maxwell Lord brings him in to help lead a Justice League International. The alien hero takes the position and becomes a sort of makeshift den mother to this group of goofy characters, particularly keeping Blue Beetle and Booster Gold out of trouble. Now relaxed in his new position, J’onn allows himself to shift into his natural Martian form during meditation and also reveals his proclivity for Oreo cookies.
A major turning point occurs for the character when the old Justice League villain Despero comes to Earth wanting to mindlessly kill his old adversaries. Despero attacks the former League-r Gypsy and kills her family. He goes on to kill a few other members, until J’onn steps up unleashing a psychic assault on the villain that fools him into thinking he has won and sends him into a hibernation state. J’onn felt himself growing distant from his team around this time, and goes on leave. As he heads for Chicago, he runs across an African-American man being attacked by a strange entity. Through bizarre arcane rituals, J’onn and the man merge into a being known as Bloodwynd. J’onn’s memories are scrambled and Bloodwynd ironically ends up joining the League. He participates in the battle against Doomsday, the monster who would eventually kill Superman, and is injured. These injuries lead to J’onn’s memories returning and he and the man split back into their individual forms.
The Martian Manhunter retained a steady place with the League in the following years, learning more about the mythology of his home world and even battling the Martian version of the Bogeyman, Fernus. On the eve a great crisis, J’onn was busy with monitor duty at the League’s moon-based Watchtower headquarters when a shadowy figure attack and caused the building to explode. J’onn was believed dead but is actually being used by the crisis’ key villain, Alexander Luthor (son of another universe’s Lex) as a living battery to collapse all parallel realities into one. With the help of Superman, Batman, and Wonder Woman, J’onn escapes and the young Luthor is defeated. Months later, J’onn is injured brutally by the villainous Black Adam and suffer severe psychic trauma. He gives himself a new form, more reminiscent of his natural alien form. Tragically, J’onn is killed by Libra, a cultist obsessed with bringing about an age of evil on Earth.
When the Blackest Night occurred on Earth, black rings falling from the sky and resurrecting the dead, J’onn was one of those who attacked his former friends. The rings had a corrupting influence on their hosts so it was not truly J’onn speaking through his body. Thankfully, Green Lantern and his allies managed to stop the influence of the black rings through the presence of a white energy. The white energy cause J’onn among others to come back from the dead. The alien has now returned to Mars, rebuilding its surface, but has recently experience phantom memories from his past that seem to tell him he is not the only Martian still alive.