Mia appeared on-screen in January 2009 as a pregnant teenager who was trying to find a home for her baby. She initially visited Dr. Richard Baker, a baby broker, to see if he could find a family to adopt her baby. Dr. Baker called Nicole Walker and told her that he had a baby to sell her. But, Mia became too nervous to go through with selling her baby and left Dr. Baker's office before Nicole arrived.
Frustrated with missing an opportunity to get a baby, Nicole demanded that Dr. Baker tell her where Mia lived. He refused and so Nicole stole the information when he wasn’t looking and set up a meeting with Mia, whom explained that she had a scholarship to go study dance in Japan, but had to put that on hold when she got pregnant. Since her ex-boyfriend, Chad, was no longer in the picture, Mia wanted to find a good home for her baby. Mia also insisted that her baby go to a solid home because Mia was the daughter of a single mother who had many abusive boyfriends. Nicole insisted that Mia's baby would be taken care of. She even brought Mia to the DiMera mansion to show her where the baby would live. Eventually, Nicole even confessed that she had been faking her pregnancy since her miscarriage and that Mia's baby would replace the baby that Nicole lost. Mia finally agreed to give her baby to Nicole.
On January 27, 2009 Mia went into labor and called Nicole. Nicole rushed to Mia's apartment. Knowing that Dr. Baker was delivering Sami's baby, Nicole told Mia that she would have to deliver the baby right there in Mia's apartment. Mia gave birth to a daughter. After some hesitation, she told Nicole to take the baby. Mia said that she did not need to see a doctor, nor did she want to look at her baby. She just wanted to sleep. Nicole took the baby and left Mia alone. Nicole went to the clinic and threatened Dr. Baker until he switched babies. Nicole took Sami's baby home to E.J. and they named her Sydney. Dr. Baker gave Mia's baby to Sami. Sami named the baby Grace.
After giving up her baby, Mia moved to Japan and tried to pursue a dancing career. But, Mia could only find work as a backup dancer, so she moved back to Salem to live with her cousin, Jamie. Nicole warned Mia to stay away from her and Sydney and Mia complied for the most part. But occasional run-ins with Nicole were always very stressful. Eventually, Mia even confided to Tony that she gave Nicole her baby, but Tony died before he could tell E.J.
But, unbeknown to anyone but Nicole and Dr. Baker, Mia did become close with her biological daughter, Grace. Mia met and started dating Will Horton. She would help him babysit "his" little sister, Grace. But Mia was worried when some kids from her old school recognized her. She never told anyone that she was pregnant, so rumors started that Mia had been in rehab. Not wanting the truth about her baby to come out, Mia allowed the rumors to continue - even going so far as to attend an AA meeting at Maggie's house with Will. Mia even supported Will through Grace's death. Mia couldn't understand why, but she felt a strong connection to Grace and grieved her death along with Will.
After Mia's cousin, Jamie, told Mia that she could no longer live with her, Maggie offered Mia a place to stay. Mia moved in with Maggie and Mickey in the summer of 2009. Shortly afterwards she got a job at the Java Café in Salem Place.
Just when things were starting to look up for Mia, they fell apart again when Chad Petersen-Woods was hired at the café. Chad was Mia’s ex-lover and, unknowingly, the father of her child. He had left her without any explanation and never knew she was pregnant. In reality, his parents sent him to military school and forbid him to speak with anyone from his “wild” past.
Mia was visibly shaken by Chad’s presence causing Will to become suspicious. Chad, however, was suspicious of the time he and Mia spent apart. His classmate, Kinsey, informed him that Mia told everyone she was in rehab. Chad knew Mia wouldn’t do drugs as he had tried to coax into doing so on several occasions and she always turned him down. Mia lied and tried to assure him she was a recovering addict, but he still held his doubt. Unsure how to get him off her back (and to ensure he didn’t find out about the baby), Mia enlisted Nicole’s help. Nicole had a talk with Chad and convinced him that Mia was in recovery (although Chad remained suspicious of Mia’s story).
Mia spent the remainder of the summer being town between her first love, Chad, and her growing feelings for Will. In August, she finally admitted to Will that she lost her virginity to Chad. Will was shaken at first, but he reassured her that it didn’t matter and they shared their first kiss.
Sometime later Mia’s world imploded around her when Chad overheard her talking to Brady Black about "the baby." Chad demanded that Mia tell him everything. She confirmed to him that she had a baby - his baby - and that baby was now living with Nicole and E.J. DiMera. Chad went to E.J. and demanded his daughter back, but E.J. refused. Nicole was furious with Mia and attempted to convince Chad that “his” baby would be better with her and E.J. Mia also tried to convince Chad of that, but he wanted custody of his child.
To make sure the rest of the truth wasn’t revealed, Nicole concocted another plan. Mia was forced to tell Chad he wasn’t Sydney’s father and, in fact, she didn’t know who was as she began to sleep with many men after Chad was sent to military school. Nicole was also ready with a fake paternity test in case one was demanded. Chad backed away from her, but so did Will, who was devastated that she lied to him yet again. Mia was crushed and had to endure her classmates calling her a “slut.”
Finally, a short time later, the devastating truth was revealed – Nicole had switched the babies and the baby Mia had with Chad, Grace, was dead. Mia and Chad were crushed as well as appalled by Nicole’s actions. Despite all of her lies, Will reconciled with Mia and supported her, but this also bonded Mia and Chad, and they began to grow close again.
Mia stood beside Will when Sydney was kidnapped, but she also began to flirt with Chad again. For the winter dance, Mia ended up accepting both Will and Chad’s invitation. Will was upset, but accepted her apology and even tried to make their relationship exclusive by giving her a necklace. Mia agreed to “be exclusive,” but was soon two-timing Will with Chad, who she was also lying to by saying she was single. Chad even broke up with his new girlfriend, Gabi Hernandez, whom Mia had been taunting with threats that she was going to steal Chad away from her. However, karma soon caught up with Mia and her lies were exposed to both Will and Chad who both dumped her.