Donatello is the pacifistic and technologically advanced of the Teenage Mutant Ninja Turtles who speaks technobabble.
Don was an ordinary baby turtle along with his brothers, until they were exposed to a Mutagen that originated from the TCRI building. Since then Splinter trained them in ninjitsu and raised them as his own children.
When he was a little older, he went to Japan with Splinter and his brothers to bury Hamato Yoshi's remains near the home of the Ancient One. While there they encountered a Bone Demon that wore an amulet that blinds the wise, but the Turtle Tots were able to see him and helped Splinter and the Ancient One defeat him. Afterwards the Ninja Tribunal erased their memories of the trip and were taken home.
Donatello became one of the Ninja Tribunal Acolytes along with his brothers. He was the first ninja shown to focus his spiritual energy through his Amulet of the Acolytes. This is perhaps due to the fact that the Acolytes training began with studying in a library, where Don enthusiastically absorbed knowledge of the secret arts. His spiritual avatar is that of a dragon.
A time window malfunction caused Donnie, his brothers, and Master Splinter to be "fast-forwarded" to 2105, hence the show's name Fast Forward. Donatello was one of two Turtles, alongside Michelangelo, that adapted best to the new lifestyle of the future. He was extremely interested in the new technology and quickly bonded with Cody Jones. Using his ideas, Cody had made many new, high-tech turtle weapons and vehicles. In the episode "The Journal", which features the Turtles going back to their own time, he uses his knowledge of the future to build new gadgets such as a fusion generator.
Most of the episodes in this season is mostly centered around him due to the plot goals of them returning to their own time as well as adapting to future technology of 2105.
After a long time, Cody and Don were able to finish repairing the time portal and were finally able to back to their own time. Unfortunately, Viral took over Serling and sent them jumping around time until Donny managed to repair Serling enough to create another time portal to their own time. But Viral took control of Serling again and was about to blast the Turtles, but Splinter took the blast.
Donatello was devastated by the loss of his teacher and father, and for some time was obsessive with gathering up all of Splinter's bits in order to restore him; constantly blaming himself for the incident. After some time when Don was faced with the choice of saving his brothers or gathering more of Splinter's bits, he realized that he should be there for his brothers more often. In the episode "Web Wranglers", Raphael has stated that Don has an IQ of 637 - a likely highly inflated stat. It should be noted that Don was the one who killed the Cyber Shredder by blasting him with the same energy beam Viral shot at Splinter at the beginning of the season. After that, he witnesses Casey and April getting married.
This season mostly focused on his goals and progress of bringing Master Splinter back to reality from cyberspace as well as him destroying the Cyber Shredder. Thus making him the main character of this season overall.
In Turtles Forever, he helps his counterpart 1987 Donatello build a dimensional portal stick that they used to get to the "1987 universe", and re-modify it to track the Utrom Shredder's trail towards Turtle Prime.
In the Legacy of Chris Thorndyke,
And he is reprised by Sam Riegel in the English dub and Yuji Ueda in the Japanese dub.