Carl Karl, nicknamed Carl the Intern, Dr. Coconut and Squirrel-Man by Dr. Doofenshmirtz, is the hapless intern and cameraman of Major Monogram. He is an intern and is very loyal to Major Monogram. He works at the O.W.C.A. for college credit.
Carl was born 17 or 19 years ago  in Chula Vista (California) . At an unknown moment five years prior to the start of the series, he started working at O.W.C.A. and was promoted to unpaid intern in no-time. 
When Dr. Doofenshmirtz asked Vanessa to pick up blueprints at Blueprint Heaven for a Space Laser-inator Ray, Carl is dressed as the lady at Blueprint Heaven. He accidentally gives real plans for a Space Laser-inator Ray to Ferb and gave Vanessa the blueprints for an Ice Cream Machine. Major Monogram then calls him a rookie for his mistake ("I Scream, You Scream").
When Major Monogram is unable to debrief Agent P due to a back injury, Carl does it instead. He made the close-up too close to his face, making his glasses the only thing visible ("The Flying Fishmonger").
When Dr. Doofenshmirtz built the Freeze-inator, it was Carl who debriefed the mission instead of Major Monogram due to the Major being unable to move because he was shot by the Freeze-inator. He accidentally knocks Major Monogram over, thus showing that he is very clumsy ("It's About Time!").
Carl also has his own theme called Carl, the Intern. He once had to disguise himself as an ice cream man because Baljeet and Buford were watching Perry and Perry couldn't get his mission. So when Baljeet and Buford were ordering Carl's ice cream, Perry went through an escape door in the ice cream truck. Then Carl zooms off, leaving Baljeet clueless about where Perry went ("Swiss Family Phineas").
During the Father-Daughter picnic, he revealed robotic replicas of the Flynn-Fletcher family. He used Lawrence Fletcher's robot to replace him for the Father-Daughter picnic competition while Carl was restoring Lawrence's memory. He also helped make the switch between the robotic version and the real Mr. Fletcher and congratulated Agent P until a kid saw them, forcing him and Agent P to quickly leave the scene ("I Was a Middle Aged Robot").
When Phineas and Ferb create a device to reverse the effects of gravity, Carl goes undercover as a boy, thinking that Phineas and Ferb are in league with Doofenshmirtz. Since Agent P is close to the boys, Major Monogram has him find Agent G, giving him suspect locations, some being the moon and Monte Carlo. Carl discovers that the boys are just having fun and returns with the news ("Undercover Carl").
When Dr. Doofenshmirtz abducts Major Monogram, Carl gives Perry his briefing, describing Major Monogram going to Tokyo for the international Good Guy convention. He also shows the letter made from cut-out magazine letters, and mentions Dr. Doofenshmirtz going to Tokyo with his daughter. However, he passes the whole situation off as a coincidence, and gives Perry the day off ("Phineas and Ferb Summer Belongs to You!").
While attending Squirrel-Con, Carl finds Agent P's hat, and since Major Monogram is too busy to do anything, Carl goes to find out what happened to Agent P and gets captured by Doofenshmirtz, discovering that Agent P had been brainwashed to become Doofenshmirtz's servant. He inadvertently helps Perry save the day when he tips juice over Perry's suit, causing Perry to go change and see the note to self he had written on his own chest, returning him to his normal mindset ("The Remains of the Platypus").
By accident, he fell under the influence of Doctor Doofenshmirtz's Ultimate Evil-inator and used his status within the OWCA to launch a full scale attack on the Tri-State Area. However, he was momentarily slowed down by Perry's interference before Perry strangely disappeared ("Where's Perry?").
His plans to conquer the Tri-State Area were severely damaged as Perry locked the control panel and only his paw print could unlock it. To this extent, Carl goes on a hunt for the lost platypus and winds up in Africa, cornering Agent P in the unexplored gorge. However, Agent P does not give into evil Carl and engages his robot duplicates in a full scale battle with aide from the African wildlife, a confused Candace, Major Monogram and Doofenshmirtz before Doofenshmirtz uses his newly built -inator to turn Carl back to his normal self. He then returns home with Monogram and Doof, but not before being promoted to the "title" of "paid intern", even though he will still not be paid as it is a title ("Where's Perry? (Part Two)").
By the end of summer, Carl already leaves for college, but somehow returns to play flugelhorn on the final song. ("Last Day of Summer")
Approximately a decade into the future, Carl continues to work at the OWCA. He has since been promoted to "Commander Carl" after Major Monogram retired to Bora Bora. A young man named Irving Du Bois now works as an intern in Carl's old place. After Dr. Doofenshmirtz gave up evil, Commander Carl, Dr. Doofenshmirtz, and Perry the Platypus started participating in Bowling Night every week. ("Act Your Age")
Carl is punctilious, motivated and dedicated. He is a bit careless and sometimes forgets to focus the camera, causing Major Monogram to be humiliated during some occasions. In one occasion in particular, Carl accidentally didn't zoom in, revealing that Major Monogram isn't wearing any pants. He is also desperate for a girlfriend. When Agent P went into his lair while his brain was in Candace Flynn's body, they at first thought there had been a breach in security and that it was a real girl, causing Carl to get very excited. They were soon under the impression that it was merely a disguised Agent P when his fedora fell onto his head. Carl was very disappointed, he walked off-screen dejectedly, saying, "Man! I thought it was a real girl" ("Does This Duckbill Make Me Look Fat?").
Carl has reddish- brown curly hair and wears purple framed aluminum glasses, dark green eyes and he also has freckles. His outfit consists of a white shirt with three white buttons, light brown pants and brown-orange sneakers. He also used to wear braces. 
When under the influence of Doofenshmirtz's Ultimate Evil-inator, he was seen wearing a black leather jacket, a pair of shades over his eyes and jeans. However, he was mostly seen in his normal clothes and a cape, his hairstyle also changed.
As Commander Carl in later life, he wore an olive-green Nehru jacket with "CC" monogrammed onto it. He has also grown a mustache.
Major Francis Monogram
Main article: Monogram and Carl's relationship
|The image gallery for Carl Karl may be viewed here.|
- His full name was revealed to be Carl Karl in the credits of "Ain't No Kiddie Ride". Prior to that, he was listed as "Karl" in the credits for most of his appearances, and his name was shown on-screen as "Carl" in "Swiss Family Phineas". (See the logo in the picture above.) Carl Karl is also used in the "O.W.C.A training video" commercials for the Phineas and Ferb: Across the 2nd Dimension video game. Strangely, he is still referred to by his first name as a grown man, "Commander Carl". ("Act Your Age")
- He drives an undercover ice cream truck ("Swiss Family Phineas", "I Was a Middle Aged Robot").
- Major Monogram calls him a rookie. This might mean that he might have started working there at the beginning of summer ("I Scream, You Scream"). This belief is contradicted in a flashback as it shows Carl secretly assigning Perry to the Flynn-Fletcher family 5 years in the past. However, it could just mean that Carl has been working for Monogram for about 5 years as some sort of volunteer and has only been promoted to 'unpaid intern' that summer. Monogram said "unpaid intern in no time" so he should have been promoted at least on his 3rd or 4th year working for the O.W.C.A. (Phineas and Ferb The Movie: Across the 2nd Dimension).
- Carl's age is not certain, but he is most likely a sophomore going to be a junior next school year, as he said he "based his sophomore thesis on quakes and seismic events" ("At the Car Wash"); however it is known that Carl is between 17 and 19 years old.
- He knows how to cook a spaghetti, but his forgetfulness prevents him from cooking it well ("At the Car Wash").
- Carl knows how to work a camera, pick up the dry cleaning, clear a paper jam, format, spell check and text edit ("Swiss Family Phineas").
- Carl is a fan of Maia Mitchell. (Phineas and Ferb Musical Cliptastic Countdown Hosted by Kelly Osbourne)
- Carl has his own website ("At the Car Wash", "Undercover Carl").
- He likes to dance to the "Dr. Coconut" song, as well as dress as the character when he dances ("Spa Day").
- It is said that he is working for Major Monogram for college credit ("Swiss Family Phineas").
- Though he was born without nostrils; therefore, he does not have a sense of smell ("Ain't No Kiddie Ride"), He said Major Monogram smelled like garlic in ("Brain Drain"), he also said a letter-stamp smelled good ("The Curse of Candace").
- His theme song has a remake ("Undercover Carl").
- He can speak French ("Invasion of the Ferb Snatchers").
- Carl can't draw very well ("No More Bunny Business").
- Carl is depicted as very clumsy ("It's About Time!").
- Carl is called Kees in Dutch. While the Dutch name Karel is closer to the original, it would be two syllables. However, in the Czech Republic, Carl is called Karel.
- Carl is afraid of the smell of garlic, even though he doesn't have nostrils ("Brain Drain", "Ain't No Kiddie Ride").
- Carl has been working at the O.W.C.A. for at least 5 years (Phineas and Ferb The Movie: Across the 2nd Dimension).
- His glasses are made of aluminum (Phineas and Ferb The Movie: Across the 2nd Dimension).
- Carl is afraid of spiders, snails and rats ("Bad Hair Day").
- He goes to squirrel conventions ("The Remains of the Platypus").
- His voice gets squeaky when he's lying/nervous ("Delivery of Destiny").
- He seems to want Monogram to be proud of him and is jealous of his son Monty. ("Minor Monogram")
- Despite having a nasally voice, Carl is actually a decent singer. ("Where's Perry?")
- He is now officially a paid intern, though the O.W.C.A. won't be paying him, it's just a title. ("Where's Perry? (Part Two)")
- So far, Carl is the only one in the O.W.C.A. (other than Perry) to know of Vanessa and Monty's relationship. Apparently, Monty owed Carl because he didn't tell Major Monogram about his secret relationship with Vanessa ("My Sweet Ride"). Monty later paid him back by convincing Major Monogram to show some gratitude to Carl. ("Thanks But No Thanks")
- He's on Major Monogram's heebie jeebie scale. ("Fly On the Wall")
- Carl has a cousin named Larry. ("Primal Perry")
- He is originally from Chula Vista, California. ("Phineas and Ferb Save Summer")
- He has a father who lives at home, according to a response on Swampy's Twitter.
- Carl Karl looks similar to Waylon Smithers from The Simpsons, which Dan Povenmire and Jeff "Swampy" Marsh has worked in the first seasons of that show.
- He also resembles King of the Hill character Hank Hill.
- "Raging Bully" (First mentioned)
- "I, Brobot"
- "Run Away Runway"
- "Fireside Girl Jamboree"
- "Jerk De Soleil"
- "Nerdy Dancin'"
Milo Murphy's Law
- "Agee Ientee Diogee" (in flashback)
- "The Ticking Clock"
- "Sick Day"
- "The Dog Who Knew Too Much"
- "Milo in Space"
- ↑ Operation Crumb Cake
- ↑ https://twitter.com/#!/mmonogram
- ↑ "Phineas and Ferb Save Summer"
- ↑ 4.0 4.1 Phineas and Ferb The Movie: Across the 2nd Dimension
"Man! I thought it was a real girl..."
— Carl in "Does This Duckbill Make Me Look Fat?"
- ↑ https://twitter.com/mmonogram/status/523498252864204800