A notable friend of Phineas is Isabella Garcia-Shapiro, a girl around his age living across the street from his current place of residence. His relationship with her as an acquaintance has proven to be very durable, however he is almost completely (if not absolutely) oblivious of her love and admiration for him.
As an incurable optimist, Phineas constantly looks on the brighter side of things. He is also extremely smart, creative, persistent, and able to endeavor in immensely large projects and activities with the help of his stepbrother. His hospitality is a driving force behind many of his plans.
On Sora's team, he and Ferb build many gadgets for the team when they go on missions in other worlds.
The most notable trait of Phineas is his enduring optimism, along with his ever-cheerful demeanor he always strives to uphold. Even in the face of the most difficult challenges that confront him, he manages to maintain his composure and keep his outlook on the situation positive. Phineas often uses his ability to boost the morale of those around him during phases of depression.
As intelligent and industrious as he is, however, Phineas has shown to be oblivious to the emotions and intentions of those around him. It's for this shortcoming of his that he fails to notice Isabella's love interest for him as obvious as she tries to make it, along with Candace's intention to get him grounded. It is possible that Phineas inherited this shortcoming from his mother considering how she always ignores Candace's often completely justifiable rants of the impossible endeavors he and Ferb would engage in and how she has always neglected to acknowledge the frustration Candace would feel when she on one occasion found herself in her daughter's position. ("What Do It Do?")
Being a rational and calm person, Phineas isn't easily angered or irked. However, he has been shown to be innovative to a fault; when Phineas is unable to express his creativity he may build up high amounts of stress. ("Bully Bromance Breakup"). On very rare occasions, Phineas's temper has been flared. The first traces of Phineas's aggravated side were seen when Candace ignored his warnings and put herself in danger ("Out to Launch") and when Baljeet's distraught wailing interrupted his morning ("The Baljeatles"). Phineas also openly showed his intolerance when Santa dismissed the entire population of his hometown as "naughty" ("Phineas and Ferb Christmas Vacation!"). He was agitated to a particularly high extent when on what came close to turning out as a pivotal event in his family's history when he finally learned of his pet platypus Perry's secret double-life as a secret agent. ("Phineas and Ferb The Movie: Across the 2nd Dimension")
Though a handful of instances Phineas has openly shown exasperation can be listed, there has only been one time Phineas was well and truly enraged. That time was on the day of the Summer Solistice, when Candace refused to cooperate with him during a critical moment when he needed for her to swallow her pride and settle for the tricycle that was the only means of transportation available for her to make it back to their house. Under the circumstances of a dwindling time frame, Phineas eventually resorted to yelling at her in a startling outburst of rage to force her to comply. ("Phineas and Ferb Summer Belongs to You!")
In Phineas and FerbEdit
Born in America in the 90s, Phineas lives in the town of Danville. When he was an infant, his mother, Linda who was a single parent at the time met and fell in love with British archaeologist, Lawrence Fletcher at a Love Händel concert. When Linda and Lawrence married, Phineas and Candace gained Lawrence as a stepfather and his son Ferb as a stepbrother. ("Dude, We're Getting the Band Back Together")
For his entire life, Phineas was raised in a reconstituted family, but is fully accustomed to it as if it were an average American family. Linda herself often mistakes him to being Lawrence's biological son. ("It's About Time!")
Phineas and his stepbrother Ferb have shared an enduring relationship, not only as step-siblings, but as best friends. They possess a common overactive imagination which has become the driving force behind their technical ability. He cherishes the memories he has shared with Ferb from their early childhood, but feels he had over romanticized some of them. ("Ain't No Kiddie Ride")
Every year from Phineas's birth, his family, often inviting some friends with them, would visit and stay at Clyde and Betty Jo Flynn's home in the mountains. Recently, Phineas would call the place Camp Phineas and Ferb.
One of Phineas's first plans was training monkeys to juggle bicycles (in the Original Story Pitch, a little bit before building the Coolest Coaster Ever). An early activity he participated in was going to a state fair and going on a "lame" roller coaster, which only went up a few feet, then dropped down in and was over after only about 3 seconds ("Rollercoaster").
On the first day of one summer, Phineas built an extremely large rollercoaster, dubbing it the Coolest Coaster Ever. After this, he built a beach in their backyard and remodeled Mount Rushmore for Candace's birthday ("Phineas and Ferb's Quantum Boogaloo", "Rollercoaster", "Lawn Gnome Beach Party of Terror", "Candace Loses Her Head").
Phineas was famous for a day due to his formation of the band Phineas and the Ferb-Tones, a mega one-hit wonder band. His band included Ferb Fletcher, and Fireside Girls Troop 46231. The band was offered by mega record company Huge-O-Records to be a client, but passed it down a la diva-tantrum. The band performed for the last time at Googolplex Mall, performing Gitchee Gitchee Goo with Phineas's sister, Candace ("Flop Starz").
Phineas was one of the first successful time travelers, reconstructing a time machine in the local museum. Traveling to 300 million B.C., Phineas and Ferb were accidentally accompanied by Candace. The time machine was destroyed by a T-Rex, and while Candace completely lost it, the boys took the time to practice patience, and waited for a message Phineas sent to get to the present. After a while, Isabella and her Fireside Girls troop showed up and rescued them. A lightning bolt struck the power cord on the machine, providing enough power for them to return back home ("It's About Time!").
Phineas is responsible for reuniting the band Love Händel for one night in honor of his parents' wedding anniversary. Phineas had no trouble convincing Danny, but needed to convince Bobbi Fabulous and Swampy through song. Eventually, the band finally performed ("Dude, We're Getting the Band Back Together"), and it seems they have stayed together, as they were featured in several episodes afterwards as well.
Phineas and his step-brother went into space, in order for them to see a star that their father named after them. Their sister accidentally tagged along, and the three went on a perilous journey through the galaxy. Surviving an asteroid field and other dangers, they ran out of fuel and stopped at an asteroid where a milkshake bar stood. There, Phineas and Ferb found out that it was really a star and that they owned it. After a while, they returned home, where Phineas was asked to go to a dance by Isabella. And he accepted stating that he and Ferb will see her there, because he didn't realize she meant a date with just the two of them ("Out to Launch").
As the middle months approached, Phineas and his friends formed Aglet Aid to raise awareness for Phineas's new found joy, aglets. The aid proved successful, and raised awareness all through Danville. A concert raised bigger awareness, but all memory of the day was erased thanks to Heinz Doofenshmirtz ("Tip of the Day").
He and his brother's interest in the creature "Nosey" caused them to go searching for it at Lake Nose on their trip there. Riding the boat Nosebud, they eventually found the beast and learned he was a kind and gentle creature, but allowed him to live his life in peace away from the eye of the media ("The Lake Nose Monster").
They as well helped their friend, Baljeet, with building a portal to Mars for his science fair project ("Unfair Science Fair", "Unfair Science Fair Redux (Another Story)").
A few days later, Baljeet asked them for their help with winning a giant watermelon contest. During this time, Heinz Doofenshmirtz caused the entire universe to grow large, but everything seemed normal to Phineas and everyone else, as it did not look different ("Attack of the 50 Foot Sister").
Phineas received a new pet, Goldie. He and Ferb built a backyard aquarium for her, complete with whales, dolphins, and octopi to keep her company. Dr. Doofenshmirtz's creation froze the aquarium, and it was released into the wild after being accidentally (and unknowingly) pushed by Candace ("Backyard Aquarium")
Phineas and Ferb discovered an alien named Meap in their backyard one day. Phineas states that Meap is the one of the most adorable things in the world. When Meap ran off, Phineas went out to search for him with a tracker while Ferb repaired his spaceship. He later revealed to Isabella that he thought she was very cute. They discovered that Meap was really an intergalactic security agent, and helped him defeat his nemesis, Mitch ("The Chronicles of Meap").
One night, while Phineas and Ferb are sleeping, Perry disappears into his lair and is told by Major Monogram that he will be assigned to a new villain, and also, a new family. Perry then leaves the following morning, leaving Phineas in a state of depression and sadness. Phineas decides to host an awareness campaign (much like he did for the aglets) and sings a song about Perry. Perry then arrives, cheering Phineas up automatically ("Oh, There You Are, Perry").
Phineas, Ferb, Candace, their parents, and Isabella get shipwrecked on a deserted island after a storm. Lawrence asks Phineas and Ferb to help build a shelter where they can stay inside, and Phineas and Ferb do so. However, they overdo it and instead makes some sort of vacation home. Despite that they were only doing what their dad said, Candace tries to bust them (the only reason being that she's angry they didn't build something that would reach the mainland).("Swiss Family Phineas")
On a visit to the beach, Phineas, Ferb, Isabella, Baljeet, Buford, and their uninvited "friend", Irving goes out to look for the lost city of Atlantis ("Atlantis").
On Tri-State Area Unification Day, Phineas and his friends decides to hijack the parade to show what Tri-State unification is all about, making giant floats of themselves, and even have Love Händel perform. Buford makes several attempts to interrupt the parade, but Phineas took precautions and managed to escape his traps. After the floats had literally floated away, Phineas and his friends continues the parade by simply pulling wagons ("Hip Hip Parade").
In the 2020s, twenty years after they built the Coolest Coaster Ever, Phineas had earned an award that was presented to him in Switzerland. Prior to that, either he or Ferb married Isabella, as she was introduced to Candace's future children as "Aunt Isabella". Which of the two married her was not stated ("Phineas and Ferb's Quantum Boogaloo"). The adult version of him was never seen but was mentioned, like Ferb's adult version.
Story of Joining Sora's TeamEdit
When Phineas, Ferb and their friends were planning to build a rocket that would travel to many planets in one day, their plans were messed up by Heartless and made their ship work only halfway and crashed into Sora's ship. After Phineas and co. had a complete tour, they offered their services to help defeat the Ansem and the Heartless so their world would be saved.