Raised in Brooklyn, New York, Mia's first appearance in Pine Valley came at a poker game in Liza's office at WRCW. Mia, Roger Smythe, Ryan Lavery and two WRCW workers gathered around a table to ante up. Ryan cleaned up until Mia arrived and he accused her of fixing the game. Mia also showed that she was skilled in fighting, explaining that she'd been taught how to defend herself by an uncle.
Mia had been blackmailing Marian over a secret, a secret that was exposed in August 2001: Marian's late husband, Larry, had had an affair. Mia was the product of that affair. Liza was devastated by the news and announced that she was out "for blood." Clearly, she did not believe that her father would have strayed. Intent on proving that Mia was not who she claimed to be, Liza demanded a DNA test. Liza offered her several thousand dollars to take the test. Mia was upset that Liza offered her money to do this but eventually agreed to take the test and tore up Liza's check. In the meantime, Adam had already secretively plucked a strand of hair from Mia and used it to prove conclusively that Mia's claims were accurate -- she really was Liza's sister.
Mia was also working for Adam. Mia had lost a great deal of money to Adam in a poker game -- and Adam was making her work it off. First Adam had Mia befriend David Hayward in hopes of getting dirt on him so he would stop blackmailing him about JR's role in stealing drugs from his room at the Valley Inn in hopes of getting his own charges dropped for drugging all of Pine Valley on the Fidelity. Then Adam convinced Mia to back off of her claims of being Liza's sister and instead focus on winning over Ryan Lavery, who Adam feared was falling in love with Liza.
Mia and Liza's relationship continued to get worse and worse. However, in tragedy a glimmer of hope flickered. After Liza suffered a miscarriage, Mia tearfully revealed to her sister that she too had lost a child. Mia stated that while she did not suffer a miscarriage, she had given up a child for adoption when she was very young.
Mia caught the eye of Jake Martin and the two started dating casually. Things heated up and the pair planned to sail around the world together. However, Jake got caught up in ex-flame Greenlee Smythe's life and later drugged by Vanessa Cortlandt. Mia had quit her job as a trainer in anticipation of leaving with Jake. So when Jake was a no-show, Mia had to accept a job as a waitress in order to pay her bills. Later, Jake offered Mia a position as a physical therapist at Pine Valley Hospital in an attempt to repair some of the damage he'd caused.
When Liza developed a brain tumor, she suddenly wanted to get close to the sister she'd never known. Mia moved into the Chandler gatehouse and helped take care of Colby as well as keep Liza sane. Unfortunately, Liza thought that Adam was falling in love with her and became irrationally jealous. This ended in December 2002 with Liza shoving Mia off of a ledge during a Chandler party. Although Mia suffered severe injuries from the several-story fall, she refused to press charges against Liza.
A few months earlier, Mia began to be blackmailed by Trey Kenyon, who had helped her give up a baby for adoption some years earlier. Mia became very nervous when the father, Frank Hubbard, came to town, and even more so when he found out she'd given birth to and given away his son. Mia confided in Jake and together they managed to convince Frank not to ruin the boy's happy family life. Mia still thinks of her son, William, every day, and has never fully forgiven herself for her decision.
In early 2003 Mia moved in with Jake and became a founder and partner in FUSION Cosmetics, along with Liza, Greenlee, Simone Torres and Kendall Hart. Jake was increasingly jealous of her career and time spent with handsome and dashing men. Her turning down his marriage proposal shattered his ego and he had a torrid affair with an intern. When Jake realized how he had betrayed Mia, he skipped town to join Doctors Without Borders, leaving behind only a "Dear Mia" letter for his heartbroken and confused girlfriend. Mia kept his loft apartment and was joined by Liza, who had recently broken up with Adam for what seemed to be the final time. On the romantic front, after several weeks of grieving, Mia became friendly with Edmund Grey, who was also stung by rejection due to his back from the dead wife, Maria, not remembering him. Rushing headlong into yet another questionable relationship, she and Edmund became lovers, and Mia went out of her way to win the approval of Edmund's obnoxious, hateful daughter, Maddie. Although Mia promised herself that she would not take this relationship too seriously, she was devastated when, after a few months, Edmund reconciled with his former wife, Maria.
Although Mia developed feelings for Kendall's ex-boyfriend Aidan, and kissed him a few times, the relationship never went anywhere. Mia kept a low profile in town until June, 2004, when Babette (FUSION's field operator for San Francisco) ran off with a surfer. Greenlee assigned a very thrilled Mia to take over in the City by the Bay, at least on a temporary basis. Mia asked Liza to join her. When Liza politely turned her down, Mia left town.