Joanna Wilton is the main villainess from "The Personal Trainer", episode 5.05 of Matlock.
She was portrayed by Leslie Easterbrook.
Joanna Wilton is the wife of wealthy roofer George Wilton, who Ben Matlock was angry with over the delay regarding his leaky roof. In the beginning of the episode, Joanna was revealed as an adulteress when she was shown in bed with her personal trainer, Harry Slade; continuing an affair that had been ongoing for five months. However, Joanna was one of multiple women who Harry was seeing simultaneously, and as Joanna herself learned, one of Harry's other women was her own daughter, Bobbie.
Joanna learned about Harry's dalliance with Bobbie when she found his lighter in the master bedroom. After George spotted it and unleashed his anger over Harry sleeping with his wife, Joanna decided to take this opportunity and her own anger at Harry to devise a murderous and lucrative scheme. After driving Bobbie to her workplace, a child care center, Joanna drove to George's parking garage and took his gun out of the glove compartment. Later on, the evil Joanna drove to Harry's home and shot her lover to death.
Joanna's plan was to frame her husband for the murder, as a pre-nup stated that she would get nothing in a divorce, but would control all of his finances if George ends up in jail. The motive was detailed by Matlock in his defense of George, and a copy of Tropic of Capricorn (which Joanna gave Harry as a gift) was found in the trunk of her car, officially revealing Joanna as the killer. After expressing defeat, Joanna was arrested (off-screen) for killing her illicit lover.