Leo makes his first appearance on 3 September 2019. He was unnamed until episode 5990 on 9 September 2019. Details of the character and storyline were also announced on the same day. Leo is the son of paedophile Tony King. Leo is first seen at the wedding of Whitney Dean and Callum "Halfway" Highway). He talks to Whitney's stepsister, Tiffany Butcher, and proceeds into pecking her cheek, which is witnessed by Tiffany's mother Bianca Jackson. Bianca warns Leo to stay away. However, Leo arrives in Walford and begins menacing Bianca. It is revealed that he is the son of Bianca's ex-boyfriend Tony and believes that Whitney had lied about Tony sexually abusing her. He threatens Bianca about money his grandmother had left him and threatens to hurt both Whitney and Tiffany if he does not receive the money.