A Force-attuned human male, Phineas Flynn resided on the desert planet of Tatooine and was sensitive to the Force. Alongside his stepbrother, Ferb Fletcher, he toiled as a moisture farmer.
On Tatooine, the young moisture farmers are enjoying the best time of their lives. They visit their neighbor, Luke Skywalker, and impress him with the modifications they performed on their speeder, utilizing power converters acquired at Tosche Station. Phineas proposes enhancing Luke's moisture farm, but Luke declines, stating that Uncle Owen prefers traditional methods.
Phineas and Ferb return to their residence for lunch. Their mother, Linda, examines their list of activities. Lawrence, Phineas' stepfather, suggests a summer camp on Naboo, while Linda proposes a ski camp on the ice planet Hoth. However, Phineas declines, asserting that neither he nor Ferb desires to leave Tatooine. After finishing their meal, he and Ferb depart.
After giving a bantha a shower, Phineas and Ferb return home, but they inadvertently bump into R2 and (unintentionally) knocks Perry off a cliff. They see part of Leia's message recorded for Obi-Wan Kenobi and assume she is referring to Ben Kenobi. Phineas explains that they were recently at Ben Kenobi's house for "Jedi lessons" and decide to return R2 to him, offering the droid a ride. R2 declines, preferring to proceed alone, which he soon does. Suddenly, after Agent P climbs up and falls off a cliff after Phineas and Ferb take off and accidentally ruins a young Tusken Raider's birthday party. It is then shown that the disc containing the Death Star plans was accidentally left in the backseat of Phineas and Ferb's speeder.
Phineas and Ferb leave their home for another task, but they then discover the disc in the backseat. Ferb informs his brother that R2-D2 is en route to Mos Eisley with Luke and Obi-Wan.
At Mos Eisley, Phineas and Ferb's speeder trails Luke's, searching for them. They visit their Toydarian friend, Blatto, who plays the disc in the head of another R2 unit. They discover that the Death Star is designed to destroy planets, but that it has one weakness, a small exhaust port that, if it comes into contact with a proton torpedo, will function as a self-destruct.
Phineas then concludes that if the Rebel Alliance possessed this disc, a lone fighter could enter that port. Phineas and Ferb decide to return the disc to R2. Baljeet then sees Phineas and Ferb with the Death Star plans. Candace goes into busting mode and chases them. Phineas and Ferb try to reach R2, but it left with pilot Han Solo and Chewbacca in the Millennium Falcon when the Stormtroopers attack. Phineas and Ferb decide to go into the cantina to find a pilot to deliver the Death Star plans.
Inside the cantina, Phineas inquires with the bartender about finding a pilot, who directs him to Isabella, a girl sitting alone at a table in the corner. Simultaneously, a female Twi'lek named Vanessa is singing a bluesy song about how "so low" she feels. Phineas introduces himself and his brother to Isabella. Phineas explains to her they need to find a ship that took off from Docking Bay 94. Isabella identifies the ship as the Millennium Falcon, the ship belonging to Han Solo, with whom she has a rivalry with ever since the Falcon cut off her own ship, the Centennial Chihuahua, during the Kessel Run when she was extremely close to finishing the run in eleven parsecs. Overcome with bitterness on the topic, she shoots Vanessa's microphone after hearing the her sing the words "so low" several times. The trio head off to her ship, but Candace discovers them and tries to shoot at them. Of course, Baljeet and Buford miss, and the three of them barely escape alive as Phineas, Ferb, and Isabella just manage to head into the ship and speed away. On the ship, Isabella warps into lightspeed, causing the two unprepared boys to crash into the windshield.
With the ship in hyperspace, Isabella turns to hear tinkering behind her. She angrily asks what they are doing, and strictly tells them not to touch her ship. Phineas begins to wonder about his family and mentions making new friends, but Isabella refuses this friendship. Nonetheless, he still asks Ferb whether or not "a girl like her and a guy like [himself]" would work out together. They finally catch up to the Falcon when they are not far from something that looks like a small moon, but Phineas recognizes the "moon" as the Death Star. The Death Star catches both ships in a tractor beam pulling them along with the Falcon. Isabella readies to shoot the ship free with the ship's lasers, but Phineas and Ferb offer an alternative to fighting.
Phineas and Ferb modify the Chihuahua to resemble a donut truck, complete with the appropriate scent. Isabella contacts Imperial Officer Jeff to disengage the tractor beam and docks at Bay 427.
Phineas, Ferb, and Isabella stealthily leave the disguised Chihuahua in search of R2-D2. Ferb then senses a presence in the Force. This presence turns out to be Perry, who is happy to be reunited with his old friends. Phineas introduces Perry to Isabella and explains to her that Perry the Platypus used to be their pet, but they disowned him after finding out he was secretly an agent with the Rebel Alliance, feeling as though he betrayed their trust, but now things have patched up. Perry resumes his mission, as do Phineas, Ferb, and Isabella.
Moments later, Ferb senses that Perry is in danger and decides to separate from the other two to help him. Phineas and Isabella then cross Candace's path, recognizing them as the Rebel sympathizers from earlier and further angered when Isabella shoots the console in an attempt to distract her ("That's coming out of my salary!"), she chases them across the battle station. Candace continues to chase Isabella and Phineas but slips on some disposal liquid left from the garbage chute and hangs from a ledge. Phineas decides to save her, much to the annoyance of Isabella. Phineas catches Candace, but she is confused as to why, since she always believed that the Rebel Alliance were the enemies, Phineas and Isabella catch up with and see R2-D2 and the others leave on the Falcon. Isabella tells they should leave immediately or they will lose the Falcon, but Phineas won't leave without Ferb. Phineas decides to trust Isabella to deliver the disc to R2-D2 despite Isabella warning him that she's not coming back. As Phineas explores the station in search of Ferb, he sees a room dousing with a red light. The red light is emitting from a modified Sith-inator. Phineas discovers it was built by Ferb, who is transformed by the Sith-inator, now wearing a Sith uniform and has Darth Maul-esque face makeup on.
Darth Ferb reveals to his brother that he modified the Sith-inator to create an army of Sith warriors. Darth Ferb offers his brother to join the Dark Side. Phineas then laughs at this, believing Darth Ferb was joking him. Darth Ferb proves that he is serious by getting out his lightsaber. Phineas refuses to fight his own brother, so Darth Ferb decides to obliterate him. With no other option, Phineas was forced to fight his now evil stepbrother, but Darth Ferb reveals a second lightsaber blade and continues the battle.
After they spar further, he activates even more blades. Phineas decides to hold off the fight so he can modify his own lightsaber. Phineas and Darth Ferb finally finish modifying their lightsabers and the fight continues. Their multi-lightsabers now also have motors to make them spin around. Their fight is interrupted by Perry and Darthenshmirtz crashing down into their area. Darthenshmirtz declares victory, but accidentally steps into his own carbonite trap. Perry attempts to help Phineas, but Darth Ferb stops him by using the Force, and also destroys Phineas' lightsaber then activates the Sith-inator to make Phineas join him in the Dark Side.
Suddenly, a laser blast hits Darth Ferb. The blast came from Candace, who came in to help. But Phineas tells her not to shoot Ferb since he is still his brother. Darth Ferb then attacks Candace and cuts her blaster. Phineas attempts to reach the inator, but Darth Ferb stops him from doing so. Candace decides to attack Darth Ferb by putting some pieces of broken Carbonite in the socks she got for Vader and throwing them at him.
With Darth Ferb distracted, Phineas throws his broken lightsaber into the inator's self-destruct port, and the inator is destroyed. Phineas, Candace and Perry look for Ferb under the rubble. After he gets out, he is himself again and Phineas embraces his brother.
Candace tells the gang they need to get off the Death Star and leads them to the bus pod station. Phineas and Ferb sees Luke and his X-Wing fighter fighting followed by Darth Vader's fighter to the port exhausted port and realizes they should leave before Luke fires at the exhaust port. As soon as they reach the station, the last bus pod leaves. Believing this to be their end, each of the group admit to some of their regrets. Phineas mentions that he was never reunited with his sister, who left the family behind on Tatooine when he was a baby. Suddenly, Candace recognizes the her brother that she abandoned years ago, and Phineas recognizes his long-lost sister. They embrace each other happily and then Candace asks about Ferb. Phineas explains that Ferb is their stepbrother from Linda's remarriage and begins to tell the story of what happened to Linda's first husband when the Death Star is finally destroyed. Fortunately, Phineas, Ferb, Candace, Baljeet, and Buford are all saved by Isabella on the Chihuahua, and Isabella finally accepts the Phineas' friendship. After the medal ceremony for Luke and Han, Phineas, Ferb, Perry and the rest throw a party, where Vanessa returns to sing a celebratory number. Candace, Buford, and Baljeet are now part of the Rebellion. Isabella asks Phineas if there is a chance they are related, and Phineas says no. Isabella says, "Good!" and gives him a kiss, causing Phineas to faint in a daze.
Phineas possesses expertise in invention, construction, engineering, modification, and piloting machinery. His accuracy is remarkable, demonstrated by his ability to precisely throw his broken lightsaber into the Sith-inator's destruction port.
He is skilled in lightsaber combat, capable of holding his own against Ferb in his Sith persona, although he is ultimately unable to defeat his brother, who proves to be more proficient in the art.
Phineas Flynn's initial appearance was in Phineas and Ferb: Star Wars, a non-canon crossover special with the Disney Channel animated series Phineas and Ferb. The special premiered on July 26, 2014. Phineas' character traits and design were based on those of his counterpart of the same name from Phineas and Ferb and was voiced by Vincent Martella. Phineas wear a similar robe to the one worn by Luke Skywalker in Star Wars: Episode IV A New Hope.