Mickey Smith lives in the same housing estate as Rose Tyler; friends since childhood, they ended up dating seriously until Rose left him to travel with the Doctor. When Rose disappeared, he spent the next year waiting for her, hoping to see the Doctor's TARDIS on every street corner, even though the authorities (and Rose's mother, Jackie) suspected him of murder and brought him in for questioning five times. During the wait, Mickey read up on the Doctor over the Internet, and became very familiar with his activities. He finds his on-again-off-again relationship with time-hopping Rose to be very frustrating; Rose feels that nothing can compare to space-time travel, not even her relationship with Mickey, who is resentful of the way that she treats him like nothing. Although he will drop everything to come running when Rose needs him, he also yearns for a more stable relationship, and he briefly goes out with Tricia Delaney although it makes him feel somewhat guilty. While Rose is taken aback by the fact that Mickey is moving on with his life, she does feel that he deserves someone better than her.
Mickey is a naturally suspicious person - he mistrusts Clive (who, he assumes, is an alien-obsessed nutter and probable serial killer) and he certainly shares a mutual dislike with the Doctor, who tries to wind Mickey up by calling him "Ricky". He is a natural coward, preferring to run and hide from trouble, and can be a bit weaselly, casually lying to cover up his real motives. His behavior and sense of humor are rather immature. All in all, even Mickey admits that he is not suited to the Doctor's life, and initially turns down the Doctor's offer to join them on their travels, although he doesn't want Rose to know.
Aside from Rose, Mickey is fond of sports (football in particular), and seems to have a fairly high sex drive. Despite the fact that these two hobbies would seem to require some degree of co-ordination and dexterity, Mickey is actually very clumsy, being particularly liable to run into or trip over things. He may have been obsessed with aliens as a child.
Mickey is a little taller than Rose, black, with fairly short hair and dark eyes. He wears a faceted earring in his left ear.