Not much is known about Casey Jones, except for the fact that he clearly knows about the existence of mutants. Casey has created his own arsenal of weapons, which he uses against his enemies; mutants and criminals alike. It is hinted that he has been down in the sewers and he might even have his own lair set up down there. In the online comic, Casey had spray painted "Jones is Everywhere" with his iconic hockey mask tagged next to it, possibly indicating that he goes go down there occasionally...
- Mutagen Man Unleashed - In his debut-episode, Casey encounters April in the hallway where he tells her that she's his tutor. Even though he proved he would be difficult to work with, he says he's willing to cooperate if it means staying on the hockey team. April agrees to help him and decides to tutor him that night in the park.When they start their session, Casey tells April that he's not interested in trigonometry and wants to be a hockey player or a bounty hunter once he graduates. Despite everything April had witnessed that day, he surprises her by asking who wants to live a normal life. When April sighs a bit, Casey shows empathy. He then notices a smudge on her face and wipes it off, which shocks Donatello, who is watching them from a rooftop.On their way back home, Mutagen Man shows up and tries to approach April. Casey steps in front of her and manages to get a couple of hits in. However, he and April barely fend him off, but they are able to shake him off and escape unharmed. They make their way back to April's apartment while watching out for anymore mutants. They make plans for their next tutoring session just as Mutagen Man prepares to go after April. Casey almost heads towards the alley where the turtles are fighting Mutagen Man when April redirects him to the other way.
- Target: April O'Neil - He meets April in the hockey ring where they strike up a conversation. He asks her why she doesn't hang out with other people, which results in her telling him that she and her friends "are fighting". He relates her situation to his friendship with his best friend Nick ending after he accidentally injured him during a hockey game. Even though both say that Casey didn't mean to hurt him, he repeats that it was something that was beyond his control. Just then, when Casey goes to change, the Foot Bots attack April. He shows up and starts fighting them off while telling April to leave him. Despite his wishes, April helps him fight the soldiers and leads a few away. After the turtles defeat Karai and her robots, April returns to the ring to find Casey unharmed.
- The Good, The Bad and Casey Jones - Casey first met Raph when he's fighting 3 members of the Purple Dragons, when Raph tries to stop him from possibly killing them. The next day at school, April wonders what's wrong with him since he got quite a lot of bruises from the fight, which he claim is from practicing hockey. He then was brought to the turtles lair and found out about the secret and everything. He later fought a foot bot with Raph and ended up being friends and joining the tea,.
- Fungus Humungous (episode) - Casey is seen at the beggining of the episode reading a paper with April and she says it's nice to have someone else to know the secret about the turtles. He later falls under the spell of the fungi and sees many rats as that is his fear but in the end he is cured.
- Of Rats and Men
- The Manhattan Project Part 1 - First he gets eaten by a Kraathatrogon and later rides one with April to stop the Kraang
- The Manhattan Project, Part 2
- The Lonely Mutation Of Baxter Stockman - He rides Kirby Bat with April to get her father cured.
- Newtralized! - Casey follows the turtles and destroys the Kraang Walker, defeating the Newtralizer.
- The Wrath of Tiger Claw - Casey gets severely injured by Tiger Claw.
- Plan 10 - Casey gets his mind switched with April.
A Chinatown Ghost Story - It's shown he has a metal plate on his skull. The Invasion - Casey Jones and Raphael are looking for Karai on the rooftops. Casey asks Raphael, while looking at some graffiti he did, if April ever talks about him. Soon some cops come and try to arrest Casey. He hits them with a Hockey stick revealing them as Kraang Droids. Soon he and Raph make it to April's house. After Leonardo comes crashing through the window, they hop into the Party Wagon. Casey drops April, Donatello, Michelangelo, and Raphael off at the base, while he looks for his little sister and father. Casey delivers a blow to Kraang Prime by driving the Party wagon into his suit. Then Casey, Raphael, Michelangelo, Donatello, April, and an unconscious Leonardo drive away to the O'Neil farmhouse. Casey talks to April about how the Kraang probably got to his father and sister because he couldn't find them anywhere.
- Within the Woods - The Creep attacks him and gets his hockey mask.
- A Foot Too Big
- Buried Secrets
- The Croaking
- In Dreams - Casey and April investigate Bernie's General to save the turtles.
- Race with the Demon - Casey and Donatello build the Turtle Racer to defeat the Speed Demon.
- Eyes of the Chimera - Casey, Mikey and Raph are abducted by the chimera.
- Vision Quest - Casey and April stay at the farmhouse training.
- Return to New York (2012 TV series episode)
- Serpent Hunt
- The Pig and The Rhino
- Battle for New York, Part 1
- Battle for New York, Part 2
- Casey Jones VS. The Underworld - After being left out of the action in the battle for the city and losing a fight against the new Purple Dragon leader Hun, Casey decides o clean the city on his own spying the Foot and the Dragons.
- Meet Mondo Gecko - Mikey and Casey befriend Mono Gecko, but Mondo's actions make him angry and he leaves them alone. Later the three of them have to race Fishface to the death.
- The Deadly Venom - Casey, April and the turtles are poisoned by Karai.
- Raphael - Casey originally viewed Raphael as evil, but after finding they have things in common (e.g. liking to fight crime), they became best friends and sometimes rivals. Mostly, they work as partners in defeating any enemy that comes their way.
- Donatello - Donatello views Casey as a rival for April's affection, but still considers him an ally.
- Leonardo - An ally; Casey seems to interact more with Raphael and Donatello.
- Michelangelo - Michelangelo and Casey don't interact as much as the others, but they are still allies.
- April O'Neil - April hangs out with Casey in school. At first, April was tutoring Casey and after sometime they became good friends. Although it was revealed that Casey prefers to hang alone with April, he is seen to hang out with her and the turtles in some episodes. Since then it has been show that Casey and April have feelings for each other. Casey shows his emotions toward April more though by crushing on her [for example in The Invasion, Part 1 when he did some graffiti on a nearby wall of him and her together].
- Splinter - Originally, Casey was afraid of Splinter due to the fact that he has a fear of rats, but has since become comfortable with being around him. Splinter has been shown to be friendly towards Casey when meeting him, as he thanked him for helping to protect his sons (the turtles) and the lair (their home). Casey told Splinter it was no problem. Since then despite his fears, Casey has had no problem being around splinter or being in the sewers.
- Punk Frogs- Casey originally hated the Punk frogs because they kidnapped and locked him and April in cages, but when the fire started he saved Attila by shoving him from the base.
- Dr. Cluckingsworth
- Mondo Gecko
- Karai- although they haven't had any contact or interaction, He along with April and the turtles have attempted to help save her from the shredder and foot a few times. He later met her in The Deadly Venom when she attempted to hunt down him, the turtles and April by poisoning and killing them all which failed. she also kissed him as she poisoned him.
- Mutagen Man
- Rat King
- Slash (formerly)
- Baxter Stockman
- Tiger Claw
- Kraang Prime
- Punk Frogs (formerly)
- Dream Beavers
- Speed Demon
- Purple Dragons
Casey seems to be a bit arrogant, a bit flirty (at least around April), quite inattentive to his school work, and he thinks highly of himself. Even with his first encounter with April, he managed to show how involved he is with himself and the fact that he thinks little of others. But he admits that he does need a tutor, as he wishes to stay on his hockey team. And while he tended to aggravate April a bit during their tutor session, he tried in his own way to be friendly and get her to enjoy herself with something besides just books. He also shows a sense of "empathy" when she shows to be exhausted from that day, and reaches out to wipe a smudge off of her face.
During their encounter with Mutagen Man, Casey became protective over April and tried his best to watch out for her. He was also very impressed by how April fights - and he then asks if encounters like with Mutagen Man happen frequently. When she answers "too often", the idea seems to excite him.
- Custom Painted Goalie Mask
- Skull Face Paint
- Hockey Glove
- Laird's Hockey Blocker Glove - with spikes
- Homemade Taser - a potato masher rigged with 9volt batteries on a drawer track with springs
- Padlock of Doom - a lock tied up to a handkerchief
- Bunch of Keys
- Custom Sheaths - made out of belts and duck tape
- Paint Grenades - spray cans
- Wooden Baseball Bat
- Eastman's Wooden Hockey Stick
- Wooden Goalie Stick
- Wooden Cricket Bat
- Custom Skates
- Spiky Pads
- Fire Breathing Bicycle
- Hockey Pucks
- Explosive Hockey Pucks
- Protective Cup
- "School isn't always my thing. When I graduate, I’m becoming either a pro hockey player or an international bounty hunter." - Mutagen Man Unleashed
- "Do you know what this is? This is Casey Jones vs. Evil Robo-Ninjas! Coolest freaking thing in the universe!" - Target, April O'Neil
- "Goongala!".- Mutagen Man Unleashed/Target: April O'Neil/ The Good, The Bad, and Casey Jones
- "Scum-suckin' mutant freaks of the world, prepare to meet Casey Jones..." -The Good, The Bad, and Casey Jones
- "The class is Pain 101. Your instructor is Casey Jones."-Casey Jones VS. The Underworld
- Casey's hockey stick has "Eastman" written over it as well as his arm protection has the name "Laird", the names of the Ninja Turtles creators.
- In The Good, The Bad and Casey Jones, it was revealed that Casey has musophobia (the fear of mice and rats), at the beginning he was even afraid of Master Splinter.
- A Casey Jones action figure was released in 2014 by Playmates.
- Casey Jones is left-handed.
- When Casey was drawing himself defeating Raphael, it was in the style of the original mirage comics.