Andi, I'm not your sister. I'm your mother.
— Bex to Andi
At the start of the show, Bex was depicted as an independent, flighty, adventurous, and sarcastic free spirit. As the plot unravels, though, it is revealed that Bex carries a lot of baggage, including resentment towards her mother, Celia, from the fight they had when Andi was a baby. Bex loves Andi more than anything, and would "jump off a cliff" to make her happy, as Bowie and Bex discussed during one episode. Perhaps Bex's definitive trait is her love for her daughter. Bex is willing to make sacrifices for those she cares about, and this trait only grows as the plot progresses. Her main objective throughout the show is to form a close bond with her daughter, and this drives many of her actions throughout the series.
However, Bex is very secretive, and will not open up to others, sometimes even her own daughter, Andi, easily. She kept Andi's dad's identity from her daughter for a long time, and doesn't like sharing her box's contents with many. Despite all of this, Bex is a very good person. She is resilient, compassionate, and kind.
Bex is the daughter of Celia and Ham Mack. For most of her life, she has lived an adventurous life, travelling the world. While still a teenager, she got pregnant and gave birth to a baby girl, Andi Mack. After a disagreement with her mother Celia, Bex left the baby Andi under Celia and Ham who raised her as their own daughter. Bex continue to travel the world and whenever she came home, she as well as her parents told Andi that she was Andi's older sister.
On Andi's 13th birthday, Bex comes back home ready to finally settle down. Andi is excited to have her cool older sister home for her birthday but Celia is not impressed. After hanging out with Andi on her birthday, Bex feels compelled to tell Andi the truth: that she is not her sister; she's her mother. She shows Andi a picture from the hospital bed with Bex holding Andi after she was born.
After exposing the secret, Bex is currently trying to make things right between her parents and her daughter. In Shhh!, she has gets herself a job at The Fringe where things are a little awkward because her boss is Brittany, a girl she used to babysit.
Bex has been struggling to be the perfect mother for Andi while at the same time acting like Andi's cool sister. This becomes a problem in Shhh! when Bex encourages Andi to stay up late watching a horror movie, against Celia's wishes. As a result, Andi gets detention the following day for sleeping in class.
Bex's relationshipw with her mother gets worse in Dancing in the Dark when Bex asks Andi to throw a dance party while the parents are away. Not only does this give a room for Amber to humiliate Bex and Andi, but it also upsets Celia so much that she gives them a silent treatment.
Celia is still not talking to them and even Andi starts avoiding Bex, because she feels like Bex is a bad influence on her. Meanwhile, Bex has been trying to figure out a way to talk to reach out to Andi's dad.
When Buffy is forced to change her her style and needs someone to talk to, she comes to Bex who helps Buffy regain confidence in herself. This makes Andi a little jealous that Bex is spending more time with Buffy than her.
In She Said, She Said, Bex tries to prove that she's responsible to Celia by buying groceries and cleaning up the house but she finds it difficult to get approval from Celia. It gets awkward when Celia visits Bex at The Fringe and realizes that Bex's boss is Brittany since Celia and Brittany have some bad history. Celia asks Bex to give her a makeover to go see Wicked. Bex is proud when Celia says she is good in makeup but it doesn't last long before Celia brings up the keyboard that Bex destroyed. Later on, Bex tries to help Andi miss school by giving her tips on how to fake being sick and ultimately offers to write a note for Andi.
While fighting with Celia on whether Andi should go to school, Bex is shocked when Bowie Quinn arrives. She introduces Bowie and Andi and tells Andi that Bowie is her dad. In Dad Influence, Bex asks for Andi's permission from school so that she could spend time with Bowie. At the end of the day, Andi wonders why Bex broke up with Bowie but Bex explains that it's partly because he's unpredictable. Bex and Andi find Bowie in Andi Shack, having invited himself to be their guest. Together, they convince Celia to allow him to stay for a while.
In Terms of Embarrassment, it's revealed that it was Bowie who walked out on Bex after a fight. He says that he always wanted to come back to Bex once he made it in life but it never happened. He apologizes to Bex and asks if she could let him back in their life but Bex isn't ready so she avoids the talk.
After Bowie leaving, Bex tries to connect more with Andi in She's Turning Into You. She takes Andi to The Fringe for a shopping spree where they try on different outfits for fun. She tries to play a match-maker for Andi and Jonah when Andi brings Jonah to The Fringe to shop for Amber's birthday gift. Bex puts make-up on Andi infront of Jonah to show him how pretty she is. Bex takes Andi to The Spoon Diner to eat baby taters and talk about Jonah Beck. Andi has so much fun that she wonders why Bex even left in the first place - they could have been having all that fun every day. Bex is ready to explain how she left but Andi just wants to talk about Jonah. The two arrive late for dinner, making Celia really mad. Bex and Celia have a very heated drama during which they debate the circumstances under which Bex left in the first place. Celia blames Bex for leaving while Bex believes that Celia sent her away. Andi runs away from the heated drama. The following day, she puts on heavy make-up before leaving for school. Celia gets scared that Andi is turning into Bex.
Following the intense drama, Bex doesn't want to stay at home with Celia. So, she gets an apartment and takes Andi there after picking her up from school. Life in the new apartment turns out to be more difficult than expected in Home Away From Home. Bex struggles to keep things running in the apartment: taking care of Andi; doing laundry and providing food in an apartment where electricity barely works. She helps Andi sneak back into the Andi Shack to get art supplies but they get busted by Celia and Ham. Following this and after realizing that Andi she is not able to fully provide for Andi, she returns her to live with Celia and Ham. However, Andi still chooses to live with Bex because it's time to embrace the new times. Bex is filled with Joy when Andi calls her "mom" for the first time.
In Were We Ever?, Bex mobilizes The Good Hair Crew to lead a protest against unreasonable dress code at Jefferson Middle School. She supplies students with prison outfits for the protest, but runs into Principal Metcalf. After being called into the Principal's office, Bex and Andi manage to convince the principal.
Bex gets a pleasant surprise when Bowie returns to town in Best Surprise Ever. Andi gets Bowie to play the song he had written for Bex. This puts Bex and Bowie in a good mood and they dance together, just like the old times. But after that, Bex lets Bowie leave. She tells Andi that she still loves Bowie but they're not getting back together. She makes it clear that Bowie is not someone they can fully count on to be there when they need him.
Bex is in for a surprise when Andi sets up a plan for Bowie to ask Bex to marry him. Bex doesn't want to give a quick answer right away. So, she just says "uhmmm..." which disappoints both Bowie and Andi.
Later at The Fringe, Bex's boss, Brittany is really impressed by Bex's makeup skills. She tells Bex that she should consider doing becoming a professional makeup artist. She tells Bex that The Fringe is not good enough for her because people only come there to buy fart machines and socks that smell like bacon. After finding out about Bowie's proposal to Bex, Brittany tells Bex she made the right decision by not saying yes. High school boyfriends like Bowie don't keep well, she says. This helps Bex make up her mind not to marry Bowie.
Bex disappoints Andi by telling her that she will not marry Bowie. The only reason she waited was because she wasn't ready to tell Andi yet. She promises to tell Bowie the next day after Chinese New Year festival. Unfortunately, during the festival, CeCe finds out about potential engagement and gives Bowie the opportunity to tell everyone the good news. Andi signals Bowie to let him know that Bex is not going to marry him. Bowie leaves the house disappointed. Bex feels bad for not telling him in good time.
Later that night, Andi finds that Bex has been keeping the photo of the boy from "Shhh!" in a box of toaster tarts. Back then Bex had told Andi that the boy was a nobody; tore the photo apart and threw it in the trash. Apparently after that, Bex removed the photo pieces from the trash, put them together and kept them in another box of toaster tarts. Andi confronts Bex to tell her who that boy is. He can't be a nobody.
Is he the reason Bex can't marry Bowie?
Bex tells Andi that she kept the photo of the boy in the box of toaster tarts because she didn't want to keep his memories in her memory box, but at the same time didn't want to let go of the past. She reveals to Andi that the relationship with that boy was very toxic and it left her torn. He's not just the reason she can't marry Bowie. He's the reason she doesn't know if she will ever get married at all. Andi helps Bex figure out that the boy in the picture is her "what if" and she needs to find closure in order to move on. Together, they burn the picture to help Bex start moving on.
This is the day that Bex left home thirteen years ago. She is sad and emotional because she hasn't been home on that date for 13 years. CeCe asks Bex and to come over to her house to remove their stuff from the closet. While at CeCe's house, both Bex and CeCe are forced to tell Andi what happened that caused Bex to leave the house. Bex tells Andi that she left because CeCe was constantly critical of her. Nothing she ever did was good enough for CeCe. It was unbearable. When it's CeCe's turn, she tells Andi that Bex left because she never did anything. All teen mom Bex wanted to do was sit and do nothing.
Andi already knows there was tension between Bex and CeCe that caused her to leave. But what is it that caused Bex to leave on that particular day? Ham is the one who finally tells what happened that day. Bex and CeCe had returned from taking Andi to the pediatrician for a checkup and were fighting over how CeCe made it look like she's Andi's mother. They got so caught up in the fight that they forgot Andi and left her in the hallway still strapped in her carseat. By the time Ham found Andi, it was almost an hour later. During the commotion, baby Andi uttered her first word, "Mama!" Bex was excited until she realized that Andi was actually calling CeCe "Mama." Realizing that she could never compete with CeCe as Andi's mom, Bex decided to leave home.
After the story, Bex tells Andi that she did this because it was the best for her and the only way they could bring her up without constantly fighting. CeCe thanks Bex for making such a big sacrifice.
Before leaving back to her apartment, Bex is told by CeCe that they're selling the house. That means Andi will lose Andi Shack. And it's up to Bex to break the bad news to Andi. Bex isn't ready to disappoint Andi. So, she refuses to tell her.
Bex is skeptical of Andi and Amber's new friendship when Andi brings Amber over for a sleepover. Bex doesn't trust Amber at all. Later that night, Bex is woken up by police after Andi is caught trespassing into a ferris wheel at night. It turns out that Amber had convinced Andi to sneak out while Bex was asleep. But then when Amber saw Jonah calling Andi, she got emotional and refused to let Andi down from the ferris wheel; then ran away when the police called. Bex and Bowie want to punish Andi for this but don't know how to punish. Bex admits to Bowie that she's only mad because Andi didn't invite her. Does that make her a bad mother? Bowie promises her that she will figure out the whole mother-thing.
They go for ice cream later during which Bex and Bowie start playing around with each other as they used to do back in high school. There might still be some hope for them.
Bex is hit with reality when she realizes that CeCe is serious about selling the house; and that she needs to tell Andi about Andi Shack soonest. Bowie helps convince Bex come to terms with the truth. He also goes to Bex apartment to help in delivering the bad news about Andi Shack to Andi.
Cyrus comes to Bex for help when he needs someone to review his script and provide honest feedback. Bex reads the script and it's terrible, but she's afraid of telling Cyrus the truth. She doesn't want to break his heart. So, she lies to Cyrus that she liked the script. Cyrus then casts Bex's boss, Brittany as the lead character and asks Bex to help produce/direct the movie from the script. Brittany hates the script and tells Bex about it. When Bex admits to her that she hates the script too, Brittany forces Bex to tell Cyrus the truth or she will do it herself. Bex tells Cyrus about it but assures him that he will get better.
Bex thinks Celia is manipulating Andi when Andi reveals that she had agreed with CeCe that they won't sell the house (and Andi Shack) as long as she spends more time at their house. Bex becomes furious when she gets a call from Andi's school telling that Andi missed school. She's worried-sick about it only to find that Andi skipped school to be with CeCe. She confronts them about it and takes Andi back. Andi helps Bex see things from CeCe's perspective. CeCe comes over to Bex's apartment to apologize and ask Andi to go to a dance class with her. Bex joins them.
After the dance, Bex goes to The Spoon with her mother and Andi. However, they notice Jonah Beck entering the diner with another girl. To avoid awkwardness, Bex and CeCe hide Andi as they walk out of the diner before ordering food.
Bex takes her sick plants to Judy's Blooms for Bowie to fix them. Instead, she finds a plant doctor called Miranda Patrick sitting in for Bowie. They quickly start bonding over how they both have two first names. Before they know it, they are soon friends. After going to pick up the plants, Bex and Miranda agree to go out together for donuts or something to celebrate their new bond. Miranda then tells Bex that she would like to ask Bowie out but only if Bex is not interested in him at all. Bex denies being interested in Bowie. So, as Miranda asks Bowie out, Bex leaves the nursery and even cancels her donut "date" with Miranda.
Bex helps Andi throw a birthday party for Bowie. When Bowie explains to Bex why he hates his birthday, Bex helps him see why he shouldn't let his father's death prevent him from starting a new tradition with his daughter, Andi.
Bex goes to a mini-golf course with Bowie and Andi. When Bowie leaves to take a call from Miranda, Bex is not surprised. But Andi is not okay with it. Bex tells Andi to give Bowie privacy but Andi insists that Bowie and Bex are soulmates. Bex later painfully watches Bowie take Miranda and her daughter to the same mini-golf course.
Bex is graduating at her professional make up artist school so that she can finally get a certificate. She is the valedictorian and is practicing her speech. She tells Andi that she doesn't want to invite her parents because CeCe wouldn't be proud of what she's accomplished. CeCe always wanted her to get an actual degree. So, they agree not to tell CeCe about it. She takes Andi to the graduation so she can take pictures. During the speech, Bex is shocked when CeCe and Ham arrive. She freezes and ends the speech. She tells CeCe that even if they are not proud of her, she is proud of herself for finally starting something and sticking to it until it's completed. CeCe surprises Bex by telling her that they are very proud of her.
At Cyrus' party, Bex helps Andi through her Jonah drama by advising her to act as if Jonah Beck isn't there. She promises to do the same when she sees Bowie at the party because she's still mad at him since she saw him at the mini-golf course with Miranda. When Bowie arrives, Bex's attempt to act cool doesn't work out so well. Bex wants to get a drawing of her and Andi from a caricature artist, Walker but then Bowie joins them. She makes it clear that she doesn't want Bowie as part of the drawing. When Bowie asks what he did wrong, Bex tells him about the mini-golf encounter. Later on, Bowie gives Bex a speech in which Bowie says how much Bex and Andi mean to him. Andi reads the letter later while Bex is lying on the couch, overstuffed with food from the party.
- Andi has always looked up to Bex as her cool fun sister. She always looked forward to Bex coming home so they could spend time together. She tried to hook up Andi with Jonah Beck. Even after revealing that she's Andi's mother, Bex still continues to act like a sister to Andi but in "Home Away From Home", Bex finally starts to become a mother to Andi.
- Bex and her mother, Celia don't seem to be in good terms, probably because she abandoned the family and went to travel the world. It doesn't help that Bex tells Andi the truth, forcing Celia to come to terms with being a grandmother.
|Celia :||Oh Bex, I wish you'd just grow up already.|
|Bex :||I have! This is it! I am here. And I'm raising my daughter. I have a job, that I like, that I'm actually good at. Believe me, I live for the day you tell me you're proud of me. But it's not gonna be today, is it?|
|— Bex to Celia, "She Said, She Said"|
- Bex was a teen mom.
- Bex is the actual mother of Andi.
- Bex rides a motorcycle.
- Bex really likes that Andi calls her "mom".
- Bex has a box filled with stuff from her past.
- Bex never told Bowie that she gave birth to her daughter, Andi.
- She moved to another house and Andi is living with her now.
- She is thinking of making some adjustments with Andi Shack when Celia and Ham planned to move.
- Bex's favorite color is possibly red because of these instances:
- It's shown that Bex's hair had red streaks from the flashbacks in "Mama". Which means that sometime after Bex gave birth to Andi, she turned her hair black again but kept having the color red in her hair.
- We see Bex used to have completely red hair in a photo of her and baby Andi. ("13")
- There is a picture of her and Bowie from when they were a couple during their teenage years and Bex has fully red hair.
| To view the Bex Mack gallery, click here.