Fiona picked up Michael Westen in Miami, Florida after he was stranded there after being burned and has since helped him numerous times in his various jobs. Fiona and Michael had a past relationship, which ended when Michael left without saying goodbye when his cover was blown. Now that she has encountered Michael again, Fiona makes efforts to pressure Michael into a more substantial relationship. Fiona also keeps up with Michael's mother, Madeline Westen.
In "Enemies Closer", Fiona has enough with Michael and walks out on him. Refusing to appear at a monitoring job, she doesn't turn up for Michael for the first time in the series. She is later kidnapped by one of her "Old Associates" who planned to put her up on auction. Michael and Sam however attack the associates dock and rescue her, despite getting her shot in the arm. Fiona has six siblings, among them are an older brother, Sean, who tries to help her kill the associate in an aborted drive-by, and a deceased sister named Claire as stated in the "Long Way Back".
Fiona has a tendency to shoot first (or blow up) and ask questions later. She is a brilliant strategist, but her preferred method is going in with guns blazing or with exploding IED. Michael frequently has to hold Fiona back.
Fiona becomes especially upset when someone abuses or endangers children as seen in "Hot Spot" when she insists on taking on a case regarding a football player whose sister was attacked by a member of a gang of car thieves, even ignoring Michael's advice that the police will handle it. This is an issue she feels strongly about and she doesn't care about letting her personal feelings get in the way of the whole thing.
Fiona also has a certain vixen-complex, using her sex appeal to her advantage in acquiring information.
Series creator Matt Nix has said about the characters relationship:
"The thing about the relationship with Fiona is…They are two people who really don't have anybody else that they can be with. Anybody else is going to be afraid of what Michael does, and it sort of turns her on, and anybody else for Fiona is going to be uninteresting. He is attracted to her, but part of what we explore over the first season is that they really are attracted with each other, and yet there is a reason they broke up. She is an incredibly chaotic person who just thrives on disorder. Violence is foreplay for her." At the end of season 5, she surrenders to the FBI and is immediately arrested for British Embassy Bombings . She is imprisoned in a maximum facility where she befriends Ayn, a fellow prisoner offering favors for favors. After a deal with the CIA, she is released after she helps catch her weapons supplier.
In the pilot episode, she spoke with an Irish accent; starting with "Identity", she has consistently spoken with an American accent as part of her effort to fit in with the Miami scene. The only time she has extensively reverted to her Irish accent is in the presence of her brother Sean, in "Long Way Back".
Michael is by far the most important man in Fiona's life. In the Pilot Fiona picked him up after he was dumped in Miami, after receiving his burn notice. Michael asks Fi, to distract the two man team FBI, Fiona agrees but she tells Michael that he owes her dinner. In the episode Broken Rules the two got into a heated fight that ended with them making love and waking up awkward the next morning or as Michael stated " you end up doing something you regret". In season 2 Fiona gets a new boyfriend named Campbell this is partially to make Michael jealous. In later episodes Campbell broke up with Fi, because he stated that Michael is "her real boyfriend". In one episode Michael thought that Fiona had died in a fire, he kept calling her phone and went crazy, only to go back to his apartment and find her alive and well. He kisses her passionately and the two make love.
In season 3 Fiona tells Michael that she cannot stand to see him about to ruin his life and tells him she is going back to Ireland. Unfortunately Fiona got kidnapped by her old nemesis, and Michael saved her life.
In season 4 their relationship goes south because Fi can't stand that Michael is lying to Jesse Porter the team's new member. In the season 4 finale, Fiona tells Jesse that she belongs out there with Michael for better or worse.
In season 5, they move in together and Fi attempts to make Michael shred documents so he can forget the past, this proves to be unsuccessful, however. After Michael is kidnapped by Dead Larry, Fi attempts to get rid of him by planting a bomb, as soon as she pulls the trigger she realizes that there was more than one bomb, after Fi tells Michael that she only planted one explosive, he takes her home and she tells him that two innocent people are dead. Knowing that he recorded her confession, Anson Fullerton manipulates Michael into burning the CIA. Fiona cannot take anymore and decides to turn herself in, Michael attempts to stop her but gets there to late as Fi, turned herself in to the FBI.
In season 6 she meet a woman named AYN (anything you need) with her help Fi manages to escape for a little while, she also finds out that someone is trying to kill her. Eventually Fi gets out of jail after she makes a deal with the CIA, sadly in the process Michael lost his brother Nate after he got shot in front of him. The team heads to Panama, where Michael tells Fi that he will quit the CIA, that he will no longer work for the government, he however breaks his promise and he and Fiona break up.
In the final season Fi is kidnapped and both Michael and Fi reminisce about the time they met in Ireland, at the end of the episode she gives a kiss in the cheek, meaning that they are officially broken up. In the season finale Fiona and Michael, are fighting for their lives, they appear to have died in the explosion caused by James. At their funeral, Jesse tells Sam that Michael and Fi missed a good funeral and wondered where they were, Sam says that they are probably somewhere with lots of C-4 and yogurt. Later in what appears to be a small little house in Ireland, Charlie is asleep in Michael's lap, Fi asks him how he is doing and he tells her that he fell asleep and if he should move him, she tells him no and that he is fine. Michael then wonders what he will tell Charlie when he is older and Fi asks him about what and he tells her "about me". Fi tells him to the tell him the truth, but Michael doesn't know where to start, so Fi tells him to start from the beginning to start with " my name is Michael Westen, I used to be a spy" with that said, Michael and Fiona kiss, having a happy ending like Fi wanted and raising Charlie as their son.
Skills and TalentsEdit
Fiona has many of the same skills as Michael Westen, albeit with a few differences. She is proficient in hand-to-hand combat, as she was able to disarm and knockout a thug holding a handgun with ease, and while in prison, she was able to defeat three prisoners using only two duct-taped rolled up newspapers soaked in salt water. She is also seen effectively using many different firearms, including handguns and shotguns. She is very accurate, as noted by Michael in a Spy Fact: "It takes a good marksman to be able to hit you at 50 feet from a moving car, but it takes a great marksman to miss while making it look like they're trying to hit you. Or markswoman, as the case may be."
Also, like Michael, Fiona knows how to adopt different personalities and accents, which she shows on a regular basis, as she originally spoke with an Irish accent, but started speaking with an American accent in the second episode to blend in. She has also used an English accent, a French accent, and a Boston accent. She also speaks French and speaks, or at least understands, Spanish, which is useful when with Michael, who doesn't speak or understand it.
Arguably her most notable skill, however, is her expertise in bomb-making. She has been shown to be so highly effective at this, that she surpasses even Michael Westen. This was shown when they, along with Sam, were taking on Felix Cole, a local gangster and car thief. Michael tried making an explosive called a "hockey puck," which was a coil of detcord on a rubber mat, but had trouble, so Fiona decided to do it, saying that she has a "more delicate touch." She also has used her expertise to call Jason Bly's bluff. When Bly tried to convince her that Michael was killed in a truck explosion, and showed her pictures of a truck Michael blew up, she knew that the truck wasn't damaged in a way that fit Bly's claim that Michael was dead.
Fiona is a very skilled driver, as she is regularly used as the driver of the group. When CIA Officer Strong and Michael were waiting for the group to arrive, an impressed Strong wondered how they got there so quickly, to which Michael simply replied, "Fi's driving."
"Well in my experience if something seems too good to be true it's best to shoot it just in case."—Fiona Glenanne talking to Michael Westen about Tom Strickler
"Damn, it's like one of those nature documentaries where one snake eats the other snake... I could never watch those." '"Really? I love them." Jesse and Fiona
- Michael: I thought you hated the idea of me working for the government again.
- Fiona: Oh, I do. But I want you to have a choice.
- Michael: You want me to have the choice, but you want me to choose to turn it down? Either way, don't we end up at the same place?
- Fiona: Michael, I hope you're never in a situation where your survival depends on your ability to understand relationships. You'll be dead in seconds.
- [From Reunion, Michael and Fiona are telling the print shop owner to cancel all of his appointments.]
- Owner: I can't just cancel on my clients last minute! I work for dangerous people, people with guns!
- Fiona: Oh, well, we have guns too. [Pulls out her handgun and points it at his head] And we are a lot more dangerous than your clients. [Adjusts her aim from his head to his crotch] I promise.
- Owner: You may not be a diabetic, but you are one sick lady.
- Fiona: You gonna make the calls or not?
- Owner: Gimme the damn phone.
Starting in June 2007, the USA Network kept a short-lived blog accounting several extra-episodical encounters that Fiona had with people in her own life. Generally the blog deals with stories pertaining to people not mentioned in the show, but occasionally characters like Madeline, Michael's Mother, are mentioned as well.
In an attempt to prove Michael wrong, for saying that she can't accomplish anything without attracting the authorities, Fiona decides to check out gardening. At the nursery she visits, she gets to know the owner, Eugene, and his teenage daughter, Lydia. After noting that Eugene is worried about his daughter and her romantic life, and deciding that gardening really isn't for her, Fiona takes it upon herself to protect Lydia from afar during her date. After tracking Lydia to the carnival, Fiona is disturbed not only by the choice of dress, but by the fact that Lydia is meeting a man much older than herself. Fiona waits until Lydia to make a visit to the restroom, and catches the older man making a move on an even younger girl. In a prompt act of retaliation, Fi knocks the pedophile out with two baseballs from the booth she is hovering around. After leaving the restroom, Lydia sees her date unconscious with another girl checking up on him, and reacts visibly with tears, allowing Fiona to move in to comfort, and to make sure she got home safely.
- Her weapons of choice are a stainless steel Walther PPK 7.65mm and her Colt .45 ACP M1911, but also she uses various shotguns over the course of the series.
- At the start of the second season, she was driving a white Honda CRV but when Michael was sold a SAAB 900 by the episode's client, he sold it to her. It was used at the end of the second season to run Carla's agents off the road when they were chasing Michael. She sold it, however, just before she got kidnapped.
- Michael is by far the most important man in her life
- She has lost one of her shoes twice once in "Identity" and the second time in "False Flag".
- In the series finale she and Michael are living as husband and wife and raising Charlie as their own