Liz Cruz is the head anesthesiologist for McNamara/Troy. She is often the voice of reason in the office and a strong-willed, empathetic woman. In addition, she is an out lesbian. During many surgeries she criticizes the idea of what type of surgery they are doing, and to whom. At one point she is even questioned by detective Kit McGraw about what it is like for her to be a person with such morals in the business she is in.
Liz bonds with one of McNamara/Troy's clients, a pre-op transsexual named Sofia Lopez. Sofia finds herself falling in love with her, but Liz decides not to further their relationship. During a stand-off involving violent criminal Escobar Gallardo, she is shot and sent to Bermuda to recover.
Liz's biological clock starts to tick and she decides that she wants to have a baby before it's too late. After being rejected by potential donors due to her age, Liz is shocked when Christian offers his sperm to her. Despite their love/hate relationship, Liz eventually accepts his offer and falls pregnant. However, Liz later aborts the baby after she is told that her child will have severe birth defects if born.
Due to a financial crisis at McNamara/Troy, Liz resigns and takes up on Julia's offer to work with her at the female-run business Spa De La Mer, where she becomes their resident anesthesiologist. At the end of the season, Liz finds herself a prime suspect in the Carver mystery as she had access to Christian's sperm and could have been the one who planted it at one of the crime scenes. She is interrogated by detective Kit McGraw, but eventually released.
Now working for McNamara/Troy again, Liz witnesses her new boss Michelle Landau in a compromising position with a mystery woman. After offering Michelle emotional support, Liz finds herself accused of sexual harassment and is almost fired. Her paths again cross with Michelle when she falls victim to an elaborate kidney theft organized by Michelle's old friend James, forcing her to recover in hospital for weeks. She later embarks on a relationship with young anesthesiologist Poppy, a fitness freak who encourages Liz to go under the knife. Liz eventually comes to her senses and ends their relationship. When Escobar Gallardo returns, Liz aims a gun at him and threatens to shoot, but is eventually talked out of it. After Gallardo is shot dead by his wife, Liz helps Sean and Christian dispose of the body.
Now residing in Los Angeles, Liz questions Julia's lesbian relationship with Olivia Lord, believing that she is simply experimenting. She finds herself attracted to Olivia, and kisses her at the office, which angers Julia.
In the first few episodes of Nip/Tuck, Cruz's last name was listed as Winters.