Fay was the long-suffering wife of Paul Mendez, an abusive man who treated his family like garbage and even forced his daughter, Nicole, into porn. Fay tried to be the best wife and mother she could, but Paul's abuse was too much for her to handle. She became meek and tried to keep the peace in her tormented family as best she could. She even worked as a waitress to support her deadbeat husband.

Eventually, because of Paul's abuse, she fell into the arms of Abe Carver. He was a young policeman whom she felt safe with, and soon fell in love with. However, after a young Brandon discovered the affair, he felt that Abe was responsible for the years that Paul beat the family. Brandon even set out to destroy him.

Years later, the real truth finally came out. It was revealed that not only were Fay and Abe lovers when Brandon was growing up, but Abe was Brandon's father! Once the truth came out, Abe and Brandon began to form a healthier relationship. Afterwards, Fay continued to work as a waitress, but wasn't heard from for over six years.

In 2009, it was revealed that Fay had moved to Cleveland, Ohio. She had relocated there sometime between 2003 and 2009. Not unlike her life in Salem, she was working as a waitress at a shady diner.

One day, Nicole surprised Fay by arriving in Cleveland with Sydney in tow. Fay was unaware at the time that Nicole had kidnapped the baby and that she wasn't really Sydney's grandmother. Instead, Nicole lied to her mother. She said that E.J. was abusing her and she was simply on the run from him. Because Fay was an abused wife as well, she took pity on her daughter and tried to help. Fay pulled favors to get Nicole money and fake passports for both her and the baby.

However, Nicole had a last-minute change of heart and decided to return Sydney to Sami and E.J. Unfortunately, while she was at the bus station ready to turn herself in, she was attacked from behind, knocked unconscious, and Sydney was stolen from her. Many people accused Fay of collaborating with Nicole and that she knew where Nicole had hid Sydney, but Fay maintained her innocence. Both Roman and Abe also agreed that Fay wasn't responsible. Eventually, Nicole was arrested and sent to prison for twenty years. Fay worried about her daughter, but remained upset that Nicole had used her – and her past as an abused woman – to trick her into helping her.

In 2010, Nicole blackmailed her way into an early release from prison. Fay was at her daughter's side to lend a helping hand and money she had borrowed from a friend. Fay continually tried to urge Nicole to start a new life anywhere but Salem. She also encouraged her daughter to do the right thing and leave the people she had hurt so badly with her crimes alone. Nicole didn't listen and remained in Salem.

In spring 2011, Fay came back to Salem to tell Nicole that about a heart condition. The doctors had told Fay that they had done all they could and she should spend her final days with her family. Nicole convinced E.J. to let Fay move into the DiMera mansion and let Nicole and Taylor care for their mother.

One day while everyone assumed she was sleeping, Fay overheard Stefano, E.J., and Fafe congratulating each other on their success. Stefano and E.J. had kidnapped Rafe and replaced him with Fafe, who worked his way toward destroying Sami and Rafe's marriage. Shocked by the news, Fay tried to call Nicole and tell her what she had just overheard.

But, Fafe caught her while she was on the phone. He drug Fay up the stairs at the DiMera mansion and then threw her down. She was injured and taken to the hospital. Fay clung to life long enough to tell Nicole that she knew a secret about E.J. But Fay was too weak to say anything more. A few hours later, Fafe snuck into her hospital room and smothered Fay with a pillow. Taylor and Nicole were heartbroken over the loss of their mother.

Fay appeared as a ghost to Nicole several times to remind her not to give up on finding out E.J.'s secret.