Rachel Dunleavy is a one-shot villainess in the WB/CW television series Smallville, appearing in the Season 2 episode "Lineage."
She is played by Blair Brown.
Years ago, Rachel worked as a nurse for Lillian Luthor, who's heart condition had worsened, and she became intimate with Lillian's husband Lionel. Their affair produced a son, Lucas, whom Lionel forced Rachel to put up for adoption. Lionel then paid Rachel a large sum of money to get him out of his life and cover up their affair, though he later placed Rachel in Dr. Friedberg's clinic, where she remained for seven years (c. 1985-1993).
In the present day, Rachel comes to Smallville, seeking her long-lost son. She believes that Clark Kent is Lucas, since Lucas' adoption was handed by Metropolis United Charities, the same agency that handled Clark's own adoption by Jonathan and Martha Kent. She meets with Clark at Smallville High School while he's at his locker and introduces herself as his birth mother, which Clark denies. His parents later meet with Rachel, and Jonathan firmly insists that she stay away from them.
Next, Rachel meets with Lex Luthor and tries to persuade him to speak to Clark on her behalf. When Lex refuses, she reveals her and Lionel's past affair, and mentions the possibility that Lex and Clark are half-brothers. Later, she gets a court order to have a DNA test to prove that Clark is her and Lionel's son, and Clark is forced to give a sample of his saliva for testing.
When Clark switches the samples to keep his alien origins secret, Rachel, believing Lionel to be responsible, confronts Lionel, who denies any involvement. Lionel then mockingly flirts with Rachel before suggesting that she be returned to Dr. Friedberg's clinic, causing Rachel to flee the mansion. Sometime later, Rachel kidnaps Lex and holds him captive in a house she bought using the money that Lionel gave her. She then calls Lionel and threatens to kill Lex unless he publicly admits that Clark is their biological son.
Sometime after that, Lionel holds a press conference and refuses to yield to Rachel's demands, prompting an angry response from Rachel. Rachel grabs an ax and tries to kill Lex, who gets his feet free and knocks her back, only to end up knocking himself unconscious. Rachel recovers and prepares to swing the ax, only for Clark to super-speed into the house and block the blow, causing the ax to shatter. Clark's invulnerability proves to Rachel that he isn't her son, and this revelation causes her to break down in tears.
Rachel is later mentioned to be placed in a mental hospital, while her son Lucas is revealed to be alive after Lionel falsely tells Lex that the boy died before his first birthday.