Louis was born to Charlie Fairhead and Baz Wilder in 1992. Just following his parents' marriage in 1998, Baz left Charlie and took Louis to live with her in Canada. Following her death in 2004, he was put into the full time custody of his father. Although Louis was taken care of, he began to feel resentment to his father due to his dedication to his job at the ED.
To cope Louis began getting involved with the wrong crowd in school and took to smoking cannabis and bunking off, which caused pressure on Charlie as he tried to keep his teenager son in check. In 2010 Louis got his partner Shona Wark pregnant, but avoided all responsibility by moving away and never got to meet his daughter Megan, who was temporarily taken care off by his father.
- Although Louis was born during the episode "Chain Reactions" which aired in September 1996, the year of his birth was retconned in 2007 in order to age the character up, changing his year of birth to 1992.
- First ever appearance was in the series 11 episode "Chain Reactions", although he was uncredited as a baby.