According to M'gann M'orzz, she is a Green Martian who was born and raised on Mars. She has 12 sisters, 17 brothers, and over 300 cousins. Among her family, M'orzz was closest to her uncle, J'onn J'onzz. Unlike most families, it seems, she was raised in a "liberal" atmosphere and disliked the mistreatment of White Martians. While observing her Uncle J'onn's adventures, M'orzz fell in love with Earth and wished to visit it. The chance finally came when J'onn J'onzz, the Martian Manhunter, returned to Mars and held a competition to find his young partner in crime fighting. M'orzz won and became a superhero codenamed Miss Martian. In reality, M'orzz is a White Martian, J'onn's niece, and had a lonely childhood on Mars. She is the daughter of a Green Martian, J'onn's sister, and a White Martian. Most of her siblings are green but she has one white brother. She saw a broadcast of "Hello, Megan!" from Martian Manhunter and immediately took a liking to the show and its star.
According to Martian Manhunter, the first time he met her was when M'orzz stowed away on his ship during his latest trip to Mars. He introduced her to television, a tool to learn about life on Earth. Miss Martian also took comfort that her telepathy could not read the minds of those on the screen. She became infamous for following a personal code of ethics that included not mind reading those she deemed "good." Since a Martian calendar has almost twice as many days as Earth, Miss Martian is 48 in Earth years and 16 in Martian. She later joined the Team as its 5th member and given the numerical designation B-05. Unlike her team mates, Miss Martian has no prior experience in the field. Aside from her inexperience, Miss Martian's other weakness is extreme heat like all Martians.
After meeting her new teammates on July 8th, Miss Martian moved into the Cave, headquarters of the Team. She continued to indulge in Earth television shows and baking. She took a human form based on Megan Wheeler, star of "Hello, Megan!" On July 18th, she presented the Team to her Martian Bio Ship. During the flight, Miss Martian revealed to the Team that her shape shifting was limited and she had not yet mastered density shifting to go through solid objects. It was later revealed that mind reading can be repelled by reciting trivial data in a foreign language. Her clothing and the ship were organic and very responsive to her mental commands. After struggling to prove herself to the Team against Mr. Twister, Miss Martian consulted with Red Tornado and came up with a plan on her own. She posed as Red Tornado to distract Mr. Twister while the rest of the Team followed her mental instructions. Twister was defeated and Superboy even apologized for over-reacting to her. During missions, if radio links are jammed, Miss Martian follows protocol and establishes a telepathic link between all teammates.
On September 3rd, Miss Martian cloaked herself and scouted ahead in the Bialyan desert. She was discovered by Psimon, who erased the past six months of her memory. Because of her telepathic link, the rest of the Team also suffered from amnesia. She reunited with Kid Flash, Artemis, and Robin and convinced them to help her by combining their broken memories and form a coherent timeline of current events. Miss Martian and Superboy were able to defeat Psimon in mental combat and grew closer to each other in the process. On September 5th, Miss Martian went with Aqualad and Superboy to visit Atlantis where she morphed a pair of gills and a mermaid tail. Her psychic abilities allowed her to translate and communicate in Atlantean. On September 7th, she and Superboy were set to attend their first day at Happy Harbor High School. Miss Martian took on a human form and went by "Megan Morse." She also suggested "Connor" for the first name in Superboy's alias. Morse was later recruited by Wendy Harris to try out for the Bumblebee's, the school's cheerleader squad, and was accepted.
On September 16th, Miss Martian and Superboy infiltrated Belle Reve Penitentiary disguised as the Terror Twins. Miss Martian, as Tuppence Terror, was hit on by Icicle Junior before she was taken to the Women's Wing. She shared a prison cell with Killer Frost and remained in contact with Superboy through her telepathy. Miss Martian also reported to Aqualad and Red Tornado, were on stand by in the Bio Ship some distance from Belle Reve. Aqualad was ready to contact the Justice League but she convinced him to stall the transmission, in hopes of learning how the supervillains planned to escape. During the uprising, Miss Martian accidentally used her telekinesis to save a prison guard. Killer Frost froze her in place. She eventually thawed out of the ice and was kissed by Superboy.
On September 22nd, Miss Martian was gravely weakened by the pyrokinetic onslaught of an android invader. Placed into a high heat cage construct, Miss Martian lost consciousness but was still breathing. Miss Martian awoke after Artemis triggered an electromagnetic pulse but knocked out again by a reprogrammed Red Tornado. She came to with Martian Manhunter at her side. On September 26th, during the Bwundan mission, Miss Martian went into camouflage mode but went unconscious upon identifying a Kobra Venom enhanced gorilla as Grodd. She awoke to Grodd who telepathically demanded her help. Solovar quickly explained the origins of Gorilla City to Miss Martian and she agreed to ally the Team with them against the Brain. She infiltrated one of the compounds and liberated the troop's children, kept hostage to force their loyalty, returned them to Boka and Primat, and rejoined the Team for the revolution.
On October 16th, Manhunter psychically linked the Team within an artificial reality for a training exercise. Miss Martian's subconscious took control of the simulation when Artemis was killed and members of the Team began to fall into a coma. Martian Manhunter discovered his niece possessed a telepathic mind far stronger than his, in terms of raw power. When he entered the reality, Manhunter was overcome by the Team's collective emotion and his thoughts were muddled. Once the other five members of the Team perished, Manhunter was able to remember his purpose and shocked Miss Martian out of the exercise. She lost confidence in her abilities. Black Canary implored her to train under her uncle and regain control again. On November 11th, Miss Martian worked with Martian Manhunter, Artemis, Green Arrow, and Zatanna to destroy a Flying Ice Fortress.
On November 22nd, Miss Martian saved the life of Garfield Logan by shape shifting her blood to match Logan's O- blood type. On November 23rd, she confronted Psimon who made her reveal her true form and recorded it. Psimon taunted her with the fear her friends and family would reject her upon learning she was a White Martian. Miss Martian blasted Psimon and rendered him into a coma-like state. Back at the Logan Animal Sanctuary, Miss Martian revealed her connection to Marie Logan (Megan Wheeler on the show) and showed a false true form, instead of her real true form to the Team. Queen Bee later confronted her and blackmailed her into cooperating or she'd expose the truth about what she was. In late December, Miss Martian posed as Dawn Danger on an unofficial mission in Europe. In order to perform tandem with Robin in a reasonable manner, she used her telekinesis. During the mission, Miss Martian's powers were taken by Parasite. Luckily, he also took her weakness to fire.
On December 30th, Miss Martian revealed her true White Martian form to the Team. The Team still accepted her and Superboy revealed he knew since they were mentally linked in the Bialya mission. Five years later, Miss Martian had gained greater control over her powers and could phase through solid objects. By November 1st, Team Year One, Miss Martian had wiped all residual Cadmus programming from Red Arrow's mind. Despite an open invitation to join the Justice League, Miss Martian remained on the Team. However, Superboy broke up with Miss Martian over the misuse of her psychic powers. He disapproved of her ripping intelligence and leaving her targets in catatonic states like Psimon would. The breaking point was when Miss Martian used her powers on Superboy to make him forget but was caught.
On December 1st, Team Year Five, Miss Martian joined Lagoon Boy aboard the Bio-Ship to track the missing Superman, Superboy, and Devastation after they vanished in Metropolis. Miss Martian infiltrated Kylstar's vessel and saved Superman, Superboy, Wonder Woman, Captain Atom, and Captain Marvel by using her telekinesis and smashing several orbs together that were projecting a neutralizing frequency on them. Soon after she started a romantic relationship with Lagoon Boy.
On January 1st, Team Year Six, Miss Martian was assigned to Delta Squad and joined in tracking down Clayface. On January 4th, she was assigned to Zeta Squad and teleported to Rann with Adam Strange. Miss Martian linked her allies mentally with Sardath and Alanna then acted as a psychic translator so everyone could understand each other. In the outcome of the mission, she used her powers more forcefully and extracted intelligence from a Krolotean Captain about the Justice League and the missing 16 hours when they were under the control of the Light. Since the process was forced with a species too alien for her to translate right away, the Krolotean was left in a catatonic state. On January 6th, 09:58 Mountain Standard Time (MST), the Zeta Squad returned to Earth. Miss Martian revealed what she learned about the 16 hours then at the Hall of Justice used her powers forcefully once again to learn of a contingency plan that involved a base on Malina Island. Miss Martian and Martian Manhunter posed as Kroloteans and stole data while the others fought the Kroloteans and Black Manta's men.
On January 26th, Miss Martian bid goodbye to Martian Manhunter before he left with others to Rimbor. On February 19th, Miss Martian was part of an all-female Alpha Squad sent to Bialya. During the mission, Miss Martian had another mental showdown with Psimon and easily dispatched Shimmer and Icicle Junior. On March 19th, during the Cape Canaveral mission, Miss Martian posed as Martian Manhunter at a live press conference and also used her telekinesis to simulate flight for Superboy, who posed as Superman. She was routed from the skies to aid Lagoon Boy. She arrived too late and as Lagoon Boy was taken away, lost consciousness while detonating a weapons platform. On March 30th, Miss Martian density shifted into a Reach Ship and freed Beast Boy and Impulse. She ran into Kaldur'ahm and performed a devastating psychic attack that left him in a catatonic state. Miss Martian gleaned the truth about Kaldur'ahm and was herself, left in a state of shock. At Beast Boy's direction, she staggered into battle but was quickly rendered unconscious by Black Beetle. As the Team made their journey home, Miss Martian was silent and unresponsive.
On April 1st, Miss Martian went to Bludhaven with Wolf, Super Cycle, Mal Duncan, and Superboy to settle into their temporary sleeping quarters. Miss Martian didn't care for the place and went with Duncan and Superboy to the Hall of Justice to gather what was salvaged from Mount Justice. However, they were interrupted by the arrival of Despero. Miss Martian refused to use her telepathy to defeat him and only used telekinesis with little result. She eventually revived Zatanna, Billy Batson, and Bumblebee. Zatanna then used Despero's own telepathy to defeat him. The next day, under the guise of John Jones, Miss Martian moved into Jones' apartment in Chicago. She declined a call from Lagoon Boy but received a visit from Superboy. On April 9th, Miss Martian was tasked with connecting to Green Beetle with a mind link and verifying the truth or lies with his story. Miss Martian was still hesitant to probe too much so Green Beetle volunteered his thoughts. Miss Martian vouched for him. She and Lagoon Boy went back to Chicago to talk but were ambushed by Deathstroke and Tigress. Miss Martian was collared and taken to the Manta Sub to repair Kaldur'ahm's mind.
Miss Martian wasn't sure if she could even repair a broken mind. Artemis went with her into Kaldur'ahm's mind. Miss Martian was immediately believed to be a threat and attacked by a mental construct of Aquagirl. Artemis broke away and brought Kaldur'ahm over. Together, Miss Martian and Kaldur'ahm began repairing the ruins of Poseidonis and his mind. After six hours, Miss Martian made some progress but needed days, even weeks. Black Manta was pleased and let her continue. However, he planned to kill her once Kaldur'ahm was restored to normal. Miss Martian refused to accept any plan that would compromise Artemis' and/or Kaldur'ahm's cover. While Tigress set off to deactivate Miss Martian's Proprietary Collar, Miss Martian was forced to fight Cheshire without any of her powers. While wrestling over a Manta Trooper's gun, Miss Martian managed to shoot and destroy the security camera watching the room but was rendered unconscious. When she came to, Miss Martian phased out of her collar and brought Sportsmaster, Cheshire, Artemis, and Kaldur'ahm to the mental plane to explain the truth. Miss Martian played her role and eventually phased out of the Manta Sub to make her escape.
On May 30th, Miss Martian and Nightwing concluded a stealth search for the Team. After several hours, Miss Martian was unable to locate them with telepathy. They landed in the Warworld's docking bay and continued the search. After being reunited with Sphere, they proceeded to save the Team and took out many Reach soldiers. Soon enough, they were reunited with the Team and encountered the runaways saved on March 30th. On June 13th, 23:45 UTC+2, Miss Martian took the Bio-Ship to Poseidonis and picked up Lagoon Boy. She took the time back to Bludhaven to break up with Lagoon Boy. She confessed she only went out with him because he made her feel good after the break up with Superboy and their relationship would never advance. On June 14th, 00:03 EDT, Miss Martian asked Nightwing about Superboy's whereabouts only to learn he went out with Wendy Harris. On June 19th, Miss Martian took Deathstroke's place shortly before the summit on Santa Prisca. She pretended to kill Kaldur'ahm and Artemis when they were outed.
Once Miss Martian revealed herself, she held Vandal Savage at sword point. Klarion and Teekl appeared and sent a giant flame construct after her. She was saved by Lagoon Boy. On June 20th, Miss Martian went to Rimbor along with Superboy and Adam Strange to present new evidence to clear the Justice Leauge. She then joined Beast Boy on Psi Squad for the strikes on the Magnetic Field Disrupters. She comforted Artemis when it was revealed Kid Flash perished in helping save the world. As of July 4th, Miss Martian and Superboy repaired their friendship. They were soon grouped into Alpha Squad with Beast Boy to answer a distress call from Mars.