Andrew was born into nobility, and because of his appearance girls have always shown great interest towards him. As a child, he met Diana, with whom he frequently exchanged pleasantries in his summer residences. The two would engage in debates over the usefulness of magic, and whether it has a place or not in modern life.
Andrew comes to Luna Nova Academy with his father. Andrew is led on a tour with his friend, Frank, and Diana as their guide. Touring the school, Diana and Frank get ahead of Andrew, who notices Akko in her bunny state from across the courtyard and approaches her out of curiosity. After getting caught in her incorrect transformation spell, he accompanies her to find the Fountain of Polaris. Along the way, he realizes her passion and intense desire to become a great witch, like her idol Shiny Chariot.
In celebration of winning the prize for the best student at his private school, Andrew's father organizes a party in his honor where the richest families and nobles are invited, including Diana. After talking to Akko about sneaking into the party, Andrew is stung by Sucy's Cupid Bee, prompting him to fall in love with Akko. When Akko flees, Andrew is confronted by his father, who reprimands him for allowing witches to enter the party. This reaffirms his contempt for magic, as well as all that prevents Andrew from becoming his heir, including forcing him to quit playing the piano years prior. After receiving encouragement from Akko to keep chasing his dreams, Andrew uses his piano playing to distract the other guests so Akko can finally swat the bee, undoing its magic. After the party, Andrew and Frank talk about what Andrew feels about Akko, and although he denies feeling any romantic affection towards Akko, Andrew admits that he is somewhat intrigued by her.
A fellow student of Andrew's at Appleton Academy, Louis Blackwell, has come to the conclusion that a man he doesn't recognize with a rat in his pocket is harboring a witch's familiar. Andrew assuages his paranoid fears and assures him it is a normal rat, promising to take it outside. Of course, Andrew knew that the rat was actually Akko disguised as a mouse and the student was another witch from Luna Nova Academy. After Louis storms away, Andrew facetiously asks them, "What gives us the honor of a visit from witches?". Notably, Andrew does not insist they leave as he did to Akko, Lotte, and Sucy in Bee Commotion.
When Amanda selfishly abandons her, Akko has a conversation with Andrew about why she came to Appleton--to find the Words--and her dream about becoming a witch who makes people happy like Chariot. While he was always respectful to Akko as a person, he shows a new willingness to attempt to understand her passion for magic, which he previously maintained was "worthless". He tries, but finds it impossible, to understand why she is so determined to do something no one asked her to do. She says it's because its something she wants to do, and asks if isn't the same for his desire to become a great statesman. He explains it is his duty to become a great leader because it's what people expect of him as a Hanbridge, and he cannot let them down. When Akko persists in asking if it's what he truly wants to do, he insists that what he wants does not matter, what he must do has already been decided. Akko questions this fatalistic attitude and explains that her dream is something she decided for herself, and she will not give up until it is fulfilled. Towards that end, she asks Andrew for information about the Holy Grail, which she believes will lead her to a Word. Andrew, although tolerant of the presence of witches on campus, draws a line at abetting their activities, especially those of a troublemaker like Akko's. Before he finishes his sentence, Akko has gone off on her own.
They meet next in a basement turned makeshift interrogation chamber, Akko (still a mouse) is tied up and Amanda is struggling to wrestle the Holy Grail out of the hands of Louis Blackwell. Andrew sees the medieval torture instruments the inquisitors intend to punish the witches with. As a Hanbridge and a student of Appleton, he cannot show sympathy outright, but he arrives at an innovative solution. He tells Blackwell that while he has no problem with his ideology, he cannot see him as a gentleman if he punishes the girls with violence when they have an established way to settle such conflicts at Appleton: a fencing duel between the knight statues.
Despite Amanda winning the duel, Louis destroys the cup, releasing Croix's magitronic device. It possesses one of the knight statues whose armor seals around Louis, but when Andrew throws Amanda the Leyline router she is able to use magic to defeat it.
When Mr. Blackwell arrives and sees the destruction from the aftermath of Amanda's fight with the statue, he immediately blames the witch. Andrew exercises his diplomatic skills a final time, persuading the Chairman that the damage is the result of Louis punishing the trespassing witch according to Appleton's tradition of a dual, but Amanda won. When the Chairman asks his son if he has been brainwashed, he (truthfully) tells his father that the situation deteriorated into chaos and the girl saved his life, which he takes full responsibility for. Andrew is confident that he can take care of the situation from there and advises the girls to head off. After thanking him for saving them, Akko flies off with Amanda, and as she looks back she sees Andrew smiling at her.
Andrew is invited by his father to the mansion of the Cavendish family. On the way, they run into Akko who also wanted to go to the Cavendish family mansion so they decide to take her. In the limo, the three are in an awkward atmosphere because of what happened at Andrew's party. After being greeted at the mansion, Andrew explains to Diana the situation of Akko and is taken to his room. At dinner with all the guests, Andrew is surprised by the reaction of Akko to know that Diana descends from one of the Nine Olde Witches. He finally grabs with his father in rejecting the relics Daryl offers them.
Andrew accompanies Diana as he goes to the shrine to perform the ritual to become head of the House of Cavendish. When Akko tries to convince her otherwise, Andrew says that despite her intrusibility, Diana should at least listen to her but she rejects it.
Outside, Andrew asks Akko why she is so determined to convince Diana, stating that they must accept the decision she has made. Andrew then tells Akko about how Diana could not perform magic in her childhood and how she spent all her time practicing magic, stating that although Diana surely wants to be in Luna Nova, the path she chose is that she is traveling.
When Maril and Meril appear, Andrew and Akko hide and listen to them talk to their mother about their plan to prevent Diana from performing the ritual. Andrew accompanies Akko to the door of the shrine and helps her open it so he can go to help Diana.
As he leaves the mansion, Andrew finds Akko's hat that she left behind.
While walking around the city, Andrew asks Frank how to contact Luna Nova so he can talk to Akko and give her back her hat, to which Frank tells him that the witches have a separate communication network so he should better return it to her in person. He also sees the people of the town making protests because of a soccer game with the neighboring country, also discovering about the growing popularity of the Emotion Refresh app.
While the disturbances in the country are getting worse, Andrew thinks that they should try to maintain peace with the neighboring country, receiving a reprimand from his father and Mr. Blackwell. After receiving an owl from Diana, he manages to arrange a meeting with Akko to return her hat. When Andrew tells her about the conflictive situation between the countries, Akko says that Shiny Chariot could make them forget their anger with her shows. Andrew says that would be a good thing, but if she really wants that she should do it herself, which Akko says she will do if they both laugh. When Akko discovers a strange object flying through the city, she leaves, forgetting her hat once more.
Andrew informs his father and Blackwell about the possible coup d'etat of the neighboring country, he gets angry when Blackwell suggests taking advantage of that to force the armies to take action.
Upon learning that the Noir Missile is heading towards their nation's rival, Andrew joins the argument between his father and Blackwood when the latter expresses his indifference towards the well-being of the missile's target nation due to his prejudice against them. At that moment, they discover that Akko and her friends are flying after it, much to Blackwood's fury. As this happens, the situation is getting worse with two missiles sent after the magitronic beast, which end up causing it to evolve by developing the ability to project guided projectiles against them. Soon after, Andrew and the others see that the entire nation expressed their support on Akko and Diana, so much that it become viral all over the world. Chariot and Croix use this to their advantage, as the support allows the civillians' hearts to generate a large amount of power for the young witches.
Seeing that his father and Blackwood had no idea about the significance of Akko and Diana's actions (Blackwood angrily demanding that entire broadcast must be shut down in spite of it already viral whereas Paul simply believes both witches only worsening the situation), Andrew ultimately stood up for his faith and ideals, having enough of his own helplessness. Fortunately, the newly arrived Prime Minister expresses his agreement with the young Hanbridge, who also requested everyone to lend both witches their support and prepare a backup plan in case of them failed. In the aftermath of the Noir Missile crisis, as everyone celebrates the young witches' success, Andrew is delighted that the broadcast of Akko and Diana allowed his father to see witches in positive light, as Paul wanted to hear his opinion about them as well as the importance of their existence.
Two months later, Andrew, accompanied by Frank, Finnelan, Headmistress Holbrooke, and Ursula (who now no longer alters her hair color as her identity is already revealed) returns Akko's hat and joins everyone's celebration when Akko finally able to fly with her broom.