Mickey Smith was a main character in Series 1 and 2 and a guest character in Series 4 and the 2010 New Year's Day Special of the revived series of Doctor Who.
He was portrayed by Noel Clarke.
He was an auto mechanic and resident of the Powell Estate who came to befriend The Doctor (in his Ninth and Tenth incarnations), Sarah Jane Smith, Captain Jack Harkness and another world's Peter Tyler by virtue of his youthful romantic relationship with Rose Tyler (who later became the Doctor's companion). An apparently typical young man — obsessed with football, sex and alien conspiracy theories — he rose to become a principal defender of not just one, but two planets Earth.
After years of living with the Tyler family on a parallel Earth, he returned to his "home Earth" and married Martha Jones another former companion of the Doctor. Despite close ties to the Torchwood Institutes of two Earths, he and his wife ultimately struck out on their own to become "freelance" alien fighters. One time, the couple were about to be killed by a Sontaran, but were saved by the Doctor (who was nearing his regeneration).
In the 2020 short story "Farewell Sarah Jane", Mickey attends Sarah Jane Smith's funeral alongside Martha and their son August.
Mickey shares similarities with one of the Doctor's later companions Ryan Sinclair.
Both lost their mothers at a young age (Mickey's mother Odessa committed suicide when Mickey was 5 whilst Ryan's mother died from a heart attack when Ryan was 13). Both their fathers walked out on them following their mothers deaths. Both were then raised by their grandmothers (Rita-Anne and Grace). Both knew another of the Doctor's companions in childhood (Mickey grew up with Rose, though Mickey was three years older than Rose) and Ryan went to primary school with Yasmin Khan).