Mickey was born around 1981. He briefly encountered the adult version of Rose in 1987, though the two had minimal contact.
His father, a key-cutter, left him at an early age after Mickey's mother died. He grew up with his grandmother, Rita-Anne Smith. The elder Smith was described by Rose Tyler as having "brought up" Mickey until her death in 2002. She died after tripping and falling over a tear in the carpet stairs, which Mickey had never gotten round to fixing; this left him with feelings of guilt
Nevertheless, when Mickey appeared to have died at the hands of the Autons, Rose twice told the Doctor, "I'll have to tell his mother," possibly indicating that Rose knew her or at least how to contact her.
Meeting the Ninth Doctor
By 2005, Mickey was a typical working-class young man, living on the same council estate as Rose and going out with her. He was caught up in the events of the Auton invasion and introduced to the Doctor, then in his ninth incarnation.
Rose did not return for a year and was declared missing. Mickey was suspected of her murder. The police interviewed him five times, but he was not arrested. Mickey spent the year unearthing information about the Doctor and running the www.whoisdoctorwho.co.uk website formerly run by the deceased Clive. He filled it with angry rants about the Doctor and mysterious events in which the Doctor had a hand. He grew isolated. Jackie was certain he had murdered Rose and turned most of the estate against him.
Return of Rose
Mickey was one of the last to know of Rose's return in 2006 and learned she was back only in the evening. This led to an awkward confrontation between the two Tylers and Mickey. He told Rose what had happened during her absence and her mother's actions. Rose convinced Mickey she was sorry and that she hadn't meant to stay away so long. The two reconciled.
Although still dismissive and even contemptuous of Mickey (calling him "Ricky" and "Mickey the Idiot"), the Doctor relied on him while trapped in 10 Downing Street during the Slitheen takeover of Britain's government. Mickey defended Rose's mother Jackie and killed the Slitheen. Following the Doctor's orders, he launched a missile at 10 Downing Street, blowing it up. His help in ending the alien threat earned him the Doctor's respect. The Doctor offered him a place aboard the TARDIS but Mickey declined, admitting the lifestyle was too much for him. He asked the Doctor not to tell Rose that he had done so. The Doctor gave Mickey a compact disc containing a computer virus that would wipe out all mention of him on the internet.
Mickey became involved in an alien war being fought by remote control. The "soldiers" in the war were abducted humans controlled by other humans who thought they were playing a video game; under the Doctor's instruction, Mickey organised the game controllers to keep the abducted humans alive
In Cardiff, Mickey told Rose he was dating Trisha Delaney. This may have been a lie to make Rose jealous. True or not, Mickey made it clear he was tired of putting his life on hold and dropping everything when she called. Although he angrily walked away from Rose at the end of that meeting, he helped her return to the Doctor to defeat the Daleks. At first happy to see her, he was angered by Rose's dismissal of the life she'd led, until she reminded him that the Doctor had also shown him a better way. Mickey remained doubtful about getting Rose back to the Doctor until she said there was "nothing" left for her on the estate now. Mickey swallowed his pride and used first his car, then a tow truck to pull open the TARDIS console so Rose and the TARDIS could communicate.
With the Tenth Doctor
He spent several annoying days with the Doctor an uninvited guest. The Doctor dominated Mickey's life without trying. He impressed all of his friends, ended Mickey's doomed attempts at a rebound girlfriend, beat him at video games until Mickey snapped that he didn't need impressing and sometimes people didn't need the Doctor. The Doctor set things up so Mickey could have a normal Sunday with Rose. This pleased Mickey.
Mickey continued his investigations into alien activity, renaming his website Defending the Earth! and soliciting help from other enthusiasts. His investigations twice saw him run into Torchwood Institute operations.
In 2007, Mickey found unusual activity at Deffry Vale High School and called the Doctor and Rose home. Meeting Sarah Jane Smith, Mickey was amused to find his suspicions validated; the Doctor had had companions before Rose. When he met K9 Mark III, he drew an unwelcome parallel between the 'tin dog' and himself. He helped evacuate the school as K9 blew up the Krillitanes and the Doctor accepted his request to join the TARDIS crew.
Mickey was delighted to visit a futuristic spaceship, the SS Madame de Pompadour in the 51st century, on his first trip in time and space. He travelled through a time window the ship had created into 1744 France, where he learned the ship's crew was killed by the repair droids to power the ship and they were using time windows to look for Reinette's "complete" self.
He was involved in an escapade on the planet Lagnos. When Rose was infected by the jealousy-eating Iagnon, helped make her intensely jealous to drive out the creature.
Leaving for Another Universe
His travels only lasted for a short while before a crack in the Time Vortex sent all three into a parallel world in 2007, where the age of the Cybermen was dawning. He met Ricky, his counterpart in that world, a tough, resolute character who led the Preachers, paramilitaries opposed to the Cybermen. Mickey saw him killed by the creatures; he also discovered that this world's version of his grandmother had not died.
Mickey saved the Doctor and Rose in the final battle against the Cybermen. However, he was increasingly unsure of his place in his home universe and the TARDIS. He remained in this world to care for his grandmother and, to an extent, replace Ricky. One of his first actions was to head to Paris to liberate it from the Cybermen.
Three years passed, from Mickey's perspective, in which he continued to battle the Cybermen.
Return and Marriage
Rose Tyler left Pete's World to find the Doctor. Mickey and Jackie crossed over and arrived on Earth after it was relocated to the Medusa Cascade in 2009. Mickey and Jackie arrived and opened fire on a group of Daleks about to exterminate Sarah Jane. He accompanied Sarah Jane and Jackie aboard the Crucible, where he was also reunited with Jack Harkness and, ultimately, the Doctor and Rose (later, the Meta-Crisis Tenth Doctor also greeted him warmly).
Mickey went into "freelance" alien fighting, convincing Martha to join him; ultimately, they were married. They were on their honeymoon when the 456 incident of 2009 began. One adventure saw them battle a Sontaran, Jask. Jask got them in his weapon's cross-hairs without their knowing it. Before he could fire, they were saved by the Doctor, who knocked Jask out from behind as a final gift to them. They spotted him and waved, but he walked away without saying anything. Mickey and Martha embraced as the TARDIS left, perhaps realising what the Doctor's appearance meant.
When first seen, Mickey was a bumbling coward; his capture by the Autons, and initial trip in the TARDIS, left him greatly shaken. When he met the Doctor again, he displayed resentment towards him. Already, though, he was braver than he had been; he tried to hold off a Slitheen to give Jackie time to escape. Despite these changes, Mickey was still clumsy, performing a pratfall while trying to capture Blon Fel-Fotch Passameer-Day Slitheen. Although still unwilling to travel in the TARDIS, Mickey changed his mind, inviting himself along, unwilling to just be "technical support" (or the Tin dog) any more.
Mickey reached a turning point when he met Ricky and witnessed his death at the hands of the Cybermen. Shown a version of himself that was braver, he rose to the challenge. He played a crucial part in the the Cybermen's defeat and chose to help rid the alternate Earth of their threat. When the Cybermen found a way to cross over to the other Earth, Mickey was the first to pursue them. ) When all of reality was threatened, Mickey again crossed Earths, this time with Jackie in tow. They faced Daleks and Mickey held their creator, Davros, at gunpoint. Choosing to return home, Mickey found love with Martha Jones; they became freelance alien hunters. Far from his original cowardly ways, Mickey now actively pursued dangerous aliens.
As Rose's boyfriend, Mickey felt a great deal of affection for her. ( This turned to surly resentment after a year's absence. He was still loyal, travelling to Cardiff to give her her passport. He helped her return to the Doctor after hearing her say there was "nothing left" for her back home. Mickey later lost all of his feelings for Rose, not having any interaction during the Medusa Cascade incident and telling the Doctor that there was no point in staying in Pete's World with Rose.
When Rose went missing for a year, Mickey suffered Jackie's suspicions. She turned the rest of the estate against him. Mickey still came to Jackie's aid when she was attacked by a Slitheen and their relationship improved greatly after that. They followed Rose to their home Earth. When Mickey made plans to stay, he told Jackie he would miss her "most of all".
Mickey was terrified of the Ninth Doctor at their first meeting, referring to him as a "thing". In the year Rose was missing, Mickey researched him, learning of the death and destruction that followed him. Although they made peace, they had a very tense relationship. At first, Mickey's relationship with the Doctor's next incarnation was not much better, but they were friendlier and less hostile during their later encounters. Mickey affectionately referred to him as "boss".
Captain Jack Harkness
During their first meeting, Mickey scorned Jack, deriding him as "cheesy". When the two met on the Dalek Crucible, years later, little seemed to have changed, Mickey referring to Jack as "Captain Cheesecake". This was soon shown to be playful banter, and the two shared a hug, albeit a longer one than Mickey preferred. Mickey also seemed nervous when he met him.
Although the two had little interaction aboard the Crucible, Mickey and Martha later fell in love. They married and became freelance alien-hunters. Little is known about about their married life, other than Mickey being slightly protective of Martha.
The Ninth Doctor at first often called Mickey by the deliberately wrong name of Ricky. This made it more ironic for him to run into a parallel version of himself, who really did go by the name Ricky. He also briefly referred to him as "Mickey the Idiot". Jack Harkness teasingly referred to him as "Mickey Mouse".