Cody Jones is the great-grandson of April O'Neil and Casey Jones in the 2003 TV series. He is the heir apparent to O'Neil Tech. In the Fast Forward season, he accidentally brought the Turtles and Splinter to the year 2105. Later, he created the powerful machine named Turtle X, which he used when participating in the Turtles' adventures. He was also learning ninjutsu from the Turtles and master Splinter.
All his life, Cody had mainly lived inside his penthouse, mainly to protect him from outside influences. When his parents passed away, his uncle Darius Dun took legal guardianship over him and position of CEO of O'Neil Tech
Cody had always been entranced by artifacts of the past, mostly connected to the Turtles, whom his great-grandparents mention in their journal. He once tried to create a time window to enable him to see the Turtles' exploits but accidentally brought them and Splinter to 2105. He had Serling, his robotic caretaker, to go and retrieve them before they get into trouble. Serling was only able to get everyone but Mikey, who was separated from the others. But thanks to the work of two geniuses (Donatello & Cody), they were able to locate him with his residue temporal signature and rescued him from the Street Phantoms.
Next day, Cody tried to reproduce the same effect for the time window but failed. He needed to repair a damaged circuit board but needed to go to O'Neil Tech to get it. Just then, Darius comes in as the others disappear. Darius lectures Cody over the importance of his safety and that it would be best to stay inside. But the Turtles convinced him to take a slide on the wild side and go straight to O'Neil Tech. So Darius decided to show him how dangerous the outside was by unleashing his Inuwashi Gunjin to capture him. But the Gunjin threaten Cody's life in exchange for their freedom. Thankfully, the Turtles arrive to save him, armed with futuristic weapons made by a transcendental lathe.
Eventually, inCody is able to repair the time window to send the Turtles back. He later watches his great grandparents' wedding though the time window.
Cody possesses a combination of both April's smarts and Casey's hardheadness. He is a technological genius, capable of creating or modifying highly advanced devices and technology. While he lacks his great-grandfather's physique, he does display Casey's same desire to fight against evil, which Cody does mainly through the use of technology.
Cody is fascinated by his ancestors, particularly their association with the Turtles, which led to his creating a collection of Turtle-oriented relics and the development of the Time Window. However, while familiar with many aspects of their adventures, Cody-like many residents of 2105-is unfamiliar with many of their 20-21st century tastes.
Cody is also good friends with Starlee, who is the only living being he is known to have spent time with besides his Uncle Darius before the Turtles ended up in the future. The two have mutual respect and attraction for each other, but Cody in particular is shy about admitting it. However, he is eager to help her in any way that he can, and has shown concern for her at times when she was endangered.
In The Day of Awakening Splinter addresses the young man as "Cody-San", a Japanese honorific usually reserved for a older or senior person. Since Cody is much younger that him and his student, to whom he instructs martial arts, a more appropriate title would be "Cody-Kun".