|Last appearance||Fire Walk with Me|
|Portrayed by||Ray Wise|
|Occupation||Attorney at law|
Leland (played by Ray Wise) is an attorney, with his primary client being local businessman Ben Horne. He is well-known and respected in the town of Twin Peaks. Together with his wife Sarah and his daughter Laura, his family seems to be perfect. When Laura is murdered, Leland’s psychological foundations begin to crumble. He experiences multiple nervous breakdowns and during Laura's funeral flings himself into her grave and must be pulled out. He remains unstable for some time.
When Jacques Renault is arrested as a suspect for the murder of Laura, Leland loses control and murders Jacques. After killing Jacques, Leland's hair suddenly turns white. Leland is arrested, but released on a personal recognizance bond pending trial due to personal assurances made by Sheriff Harry S. Truman that he does not pose any danger to the community. Leland's behavior at times appears normal but he behaves manically happy at times before crashing into grief. The arrival of his niece, Madeleine Ferguson, who looks almost exactly like Laura (both roles are played by Sheryl Lee), is of great help to him in learning how to deal with his daughter’s death.
It is eventually revealed that, as a boy, Leland met a strange neighbor who turned out to be a demonic entity named BOB, who would possess him throughout his life. It is also implied that BOB molested him as a child. As an adult, Leland molests and rapes Laura throughout her teens, all the while controlled by BOB. It is difficult to tell while watching the series when Leland is truly in control of himself and when he is being possessed by BOB. It is implied that Leland killed Jacques Renault on his own – not under BOB's control – and that Leland is lost from that point: he is no longer able to stop BOB and is completely taken over (physically manifested by the change of hair color and a dramatic change in behavior). The changes from this point help Cooper to finally identify him as BOB's "host".
Leland is eventually exposed as the murderer of both his daughter and his niece Maddy and is arrested by FBI Special Agent Dale Cooper and Sheriff Harry Truman. In the film he is also revealed to be the killer of Teresa Banks. He later dies in custody following his bizarre interrogation on the night of his arrest. BOB takes control of Leland and forces him to run headfirst into the metal door of an interrogation room. At the moment of his death, Leland remembers the crimes he committed under BOB's control. After Cooper recites the last rites from the Tibetan Book of the Dead, Leland sees a vision of his daughter Laura and dies. Cooper explains to the widowed Sarah in the following episode that he believed it was Laura forgiving Leland and welcoming him into the afterlife.