Leonardo, "Leo" for short, is the leader of the Ninja Turtles.
Leonardo is the most serious and focused of the team. Being the designated leader of the group, Leonardo is very enthusiastic about his role. He is also a big science-fiction fan (or "nerd" as referred to by Raphael). His favorite series is Space Heroes while his favorite character from the show is Captain Ryan. Leo has a habit of memorizing Captain Ryan's best lines from the show and repeating them during battle. Leo is so caught up with Space Heroes that he relies on Ryan's character traits more than on his own intuition which often causes his brothers (especially Raphael) to question his leadership.
For the most part, he tries to be the mature and responsible sibling, but there are times where he can be as childish as his brothers, such as teasing Donnie for losing to a mutant monkey and trying to be like an unrealistic TV character, although Leonardo often tries to comfort his brothers when they are scared or upset, mostly Mikey. He comes up with most of the plans and strategies while he and his brothers are fighting bad-guys or training in their lair. After meeting and fighting Karai, he gained a small crush on her, despite being the daughter of Shredder. His crush on her does not overrule his love for his love for his brothers, threatening Karai if she ever harmed them.
To date, his only real flaws as a leader are lack of experience and his teenager status- causing him to occasionally make impulsive decisions that might make the situation worse, as well as his brothers sometimes not obeying his orders, and a desire to be cool that results in him making rather poor taunts in battle, such as introducing the team as the "Mighty Mutants" or "Turtles of Justice", or telling a scientist experimenting with a monkey that they'd had enough of him "monkeying around."
Leonardo is shown to be quite selfless when it counts. He almost sacrifices himself twice to save his brothers and the world.
Powers and abilities
Leo's "bravery", determination, and will-power makes him a great leader. He often tends to fight in a more traditional Japanese martial art style. Leo is stealthy like all his brothers, and like them he can hide in the shadows, sneak around without beind detected, and use hand to hand combat. Leo's more balanced though, being "fast like Mikey", strong like Raph, smart like Donnie, and skilled. He is highly skilled in the fighting style Niten Ichi-ryū.
Leonardo and his brothers were once ordinary turtles; when they were infants, they were adopted from a pet store by Hamoto Yoshi (Splinter). When their soon to be father walked passed a strange man, he felt something odd about him and followed. Unfortunately, Splinter gave away his position when he accidentally stepped on a rat's tail. The Kraang found him and attempted to kill him, but Splinter fought back hard. In the end, the Kraang dropped the canister of mutagen causing the turtles and Splinter to mutate. Splinter came in contact with a rat last, thus mutated into a rat, while Leonardo and his brothers, after coming in contact with Splinter when he was human, mutated into humanoid turtles. Splinter knew they would never be accepted in society, so he took them to the sewers, made a home down there (in an abandoned subway), and made the four turtles his children. Knowing the world would be dangerous and there would be a time where they want to explore the outside world, Splinter trained the boys in the art of Ninjitsu. Leonardo and his brothers were named after great renaissance artists from a book Splinter fished out of the storm drain.
Leo along with the other turtles turned fifteen on their mutation day, and went up to the surface for the first time. He took to watching Space Heroes, before heading out. They discovered the Kraang and Snake kidnapping April O'Neill and her father. After a failed attempt at saving them, the Turtles head back home, where Splinter realised that they weren't ready to go to the surface, and in another year they might be ready. The humans, however, can't wait that long, so Splinter put Leo in charge to better coordinate themselves. The Turtles come against Snake, who got mutated into Snakeweed. They defeated Snakeweed, and saved April, but failed to rescue her father. Leo told April that they would not rest until they found her father.
Turtle Temper: Leo once again leads the turtles on a mission involving the Kraang, only to be captured on video by Vic. Leo later tells Raph that he has to go home since he caused them to fail the mission. Leo is seen with Don and Mike trying to save Vic and later fighting Spider Bites, and is happy to see that Raph came back to help them defeat Spider Bites.
New Friend, Old Enemy: Leo does not do much in this episode other than leading the Turtles during their battle with the foot and Leading Don and Raph to save Michelangelo from Chris Bradford, and later fighting Chris Bradford and Xever in the sewer.
I Think His Name is Baxter Stockman: Leo skateboards with the other turtles, and is upset that he and the others got grounded for a week by Splinter. When Raph and the others want to sneak above ground, Leo tells them no, but he later follows them when he sees that they are going anyway. Leo helps defeat Baxter Stockman in the episode.
Metalhead: Leo once again leads the turtles when fighting the Kraang. Leo is not a fan of Metalhead, and tells Don that Metalhead can't help them because he is too loud and clumsy. Leo is later seen playing an arcade game in the lair with Raph and Mike after they defeated the Kraang that controlled Metalhead.
Monkey Brains: Leo led the turtles in the chase after the mutated monkey and the fight against Falco.
Never Say Xever: Leo shows mercy on a member of the Purple Dragons street gang and Raphael believes this is a show of weakness. Leo leads his brothers in all of the fights against the Foot and, in the end, his show of compassion to the gang member helps them to win the day. This is the first episode to teach Leo a lesson about "crossing the line."
The Gauntlet: Leo leads the ambush on Pigeon Pete and leads the raid on the Kraang base. He leads the turtles in battle against Xever and Bradford at the mutagen bomb. When the Shredder attacks, Leo is the one he presses for information about Splinter.
Panic in the Sewers: Leo leads his brothers in the fight against Dogpound and was the only one to successfully use a smoke bomb to escape. When April is captured by Dog Pound, Leo nearly loses it untill Raph uses a line from Space Heroes to snap him out of it. Leo then comes up with the idea to use Donnie's new patrol buggy to chase the van down. Leo and Mikey chase down Dog Pound and manage to ignite the chemical in the tanker and save their lair.
Mousers Attack!: Leo teams up with Raph in the so-called "A-team". They go to retrieve April's phone from the Purple Dragons and stays to track down the Mousers. He and Raph discover Baxter Stockman behind the robots and are sprayed with a radio-isotopic mist that tags the Mousers in on them. They are then chased across the city by an army of Mousers untill they finally lead them back to the Foot hideout where they rescue Donnie and Mikey.
It Came From The Depths: Leo is hesitant about Leatherhead as are most of the turtles. He leads Donnie, and Raph on their search for the power cell and participates in the battle against the Kraang to defend Leatherhead in his lair.
I, Monster: Leo is not so hesitant in a training session, and is able to punch Splinter for the first time in their family's history. When Splinter's mind is taken over, he tries to get his sensei back by calling him by his human name, and for the first time "father".
New Girl In Town: Leo met Karai, getting a crush on her . He goes to April's to get advice, but she also tries to warn him. He lets Raph try his hand at leadership. On top of the Biarly Building, Karai tries to coax Leo into stealing a valuble katana, but he does not. When Snakeweed attacks, he tries to get Karai to fight, but she leaves.
The Alien Agenda: Leo is next to learn a valuble lesson: never trust a Foot agent, escpecially if it's a girl. He continues to turst her until she leaves him. He tells the truth to his bros and Splinter.
The Pulverizer: Leo doesen't act out much in this episode except getting his "drivers license" because he's least likly to hit something just for entertainment. He also tells Donnie to fix up the Shell Raiser and taking the Pulverizer home.
Baxter's Gambit: Leo does act a little more when he tries to lead the turtles and their enemies out of the labyrinth.
Enemy of My Enemy: Leo leads the team stopping the Kraang and their ship. He makes a deal with Karai to stop the Kraang. He often acts stubborn always putting Karai first over his brothers and enjoying it. He also finds out that she is the Shredder's daughter and gets upset that she wouldn't be interested in him anymore.
Karai's Vendetta: Leo doesen't act much in this episode except trying to stop the Kraang from poisoning the water supply. He also supports Splinters idea that April has to stay in the sewer until the Kraang are defeated.
The Pulverizer Returns!: Splinter tells the boys to switch weapons; Leo gets the bo staff, where as Mikey gets his swords. When Splinter takes the turtles' weapons away, he uses a pipe to fight. He witnesses Pulverizer mutate into a giant blob.
Parasitica: Leo got stung by a mutant parasitic wasp, being hypnotized to protect its egg. He brought the egg to the lair insisting to study it. And when he bit Raph, he infected him, resulting Raph to be hypnotized too.
- Raphael: Leo is the leader and Raph disagrees with that. Raph does not really like the idea of Leo being the leader and always questions his leadership. They also fight the most out of the brothers and are always getting into arguments. You could call them "friendly rivals". Raph, however, thinks he's a better fighter than Leo, and that he deserves to be the leader. Raph is also Leo's younger brother, so he is still protective over him, and Raph can be protective of Leo, but not as much as he is with Donnie and Mikey. Leo is seen to yell Raph's name everytime he's hurt. As of I, Monster and/or New Girl In Town, it seems like Raph is more accepting and open to Leo's leadership. He also admits that he needs him. Leo even agreed with Raph that they were the strongest fighters. Despite all the sibling rivalry, they seem to be very close, they love each other no matter what, and will watch each other's back.
- Donatello: Leo and Donnie get along very well, but just like his other brothers, Leo will be annoyed by Donnie's constant smarts, such as the time where Raph hits Donnie for doing so and Leo points out his satisfaction. Despite that Leo really respects Donnie for his intelligence and inventions, while Donnie respects Leo as a leader. They rarely ever argue, but in The Gauntlet, Leo was yelling at him for not expecting a very complicated mutagen bomb. He even was angry that Donnie took off to fight the Kraang in "Rise of the Turtles." He even got annoyed at him for teasing him about karai. Leo, along with Raph, didn't really see Donnie, or Mikey, as a strong fighter in "Mouser attack" and would constantly get in their way in the battle against the purple dragons, call them the B-team, and even made them go after the phone while him and Raph went after the Mousers; something he regretted in the end. When Donnie and Mikey proved their strength, Leo and Raph found new found respect for them thus recoiled their relationship. They seem to be pretty close as brothers. Leo loves Donnie as much as his other brothers and will do anything to protect him.
- Michelangelo: Mikey is Leo's youngest brother, and although he is annoyed by Mikey's annoying personality at times, it is shown that Leo is mostly protective over Mikey and he doesn't get annoyed by him like the other two does. Like in Panic In The Sewers, where they team up to stop the tanker and Leo tackles Mikey quickly after throwing the water balloon to safety. Although they don't spend much time personally, they both care about each other awfully a lot. In New Girl In Town, when Leo comes home with red eyes and Mikey thought he's been crying, he immediately went over to give his leader a comforting hug. Instead of pushing him away like the other two most probably woud, Leo just lifts him up and set him down away from him. When Mikey was kidnapped by Dogpound, as Chris Bradford, in New Friend, Old Enemy, he pat him on the head as a sign of relief that his baby brother was okay when they rescued him. Leo seems to be as protective of Mikey as he is with his brothers, even going along with Raph's threat on Leatherhead, if he harmed Mikey. He, along with Raph and Donnie, were even angry that Baxter Stockman, when he swung Mikey around by his Kusarigama chain, and was even worried when the crazied scienetist knocked Mikey back hard. Leo, along with Raph, didn't really see Mikey, or Donnie, as a strong fighter in "Mouser attack" and would constantly get in their way in the battle against the purple dragons, call them the B-team, and even made them go after the phone while him and Raph went after the Mousers; something he regretted in the end. When Mikey and Donnie proved their strength, Leo and Raph found new found respect for them thus recoiled their relationship. Leo doesn't really seem to trust Mikey too much as a partner as seen in "The Guantlet" where he didn't want to work with him, due to him being annoying and accident prone, but none the less worked well with him in "Panic in the Sewers." Leo seems to act more like a parental figure towards Mikey and also seems to be able to give into Mikey easier when he gives him the puppy-dog eyes.
- Splinter: Leo is a teacher's pet, and craves Master Splinter's approval, attention, and appreciation. They are like Father and Son, and of course, Master Splinter taught Leo everything he knows about ninjitsu. Leo gets along with Splinter the most out of all the characters, and fails to find a compatible reason for getting out of a certain punishment. Splinter also finds Leo a bit overconfident as a leader at times, and so his wisdom doesn't exactly reach through Leo until he realizes it. Splinter see's Leo as an excellent student and leader, but wishes Leo would trust himself and not try to act like Captain Ryan from "Space Heroes." When his father was under control of the Rat King, Leo was the one who got him to snap out of it, reminding him who he was and called him father, even giving Splinter a hug when he was back to normal. Like with the other turtles, Splinter is very protective of Leo.
- April O' Neil: April and Leo are good friends, and Leo is very determined to save April's father. Leo along with his family were against her going to spy on the kraang, showing he's protective of her. He and Donnie seem to interact the most with her out of all the turtles. Leo see's April as a sister and acts respectful and gentleman like around her. Also, after meeting Karai, he went over to her place to talk to April about it. She went berserk after Leo mentioned how she's in the Foot Clan by slapping him with her magazine while yelling and tried to warn him.
- Shredder: Leo first saw him in The Gauntlet and fought against him alongside his little brothers. Leo hates Shredder for the things he's done to his master, trying to kill him and his brothers, and would do anything to defeat him.
- Karai: She is introduced as his rival. He thought that she could be good and that she understood honor. Much like Batman and Catwoman. However this proves to be a problem, for because they work for two different people with different morals, who are enemies, their own morals tend to clash and don't see eye to eye. Leo was also shocked that Karai was Shredder's daughter. He was even heartbroken when he failed to get her on his side in Enemy of My Enemy.
- Leo is voiced by actor Jason Biggs, best known for his role as Jim in the American Pie film series.
- Leo admires Captain Ryan from his favorite show, Space Heroes.
- Leo was named leader because he asked, not by Splinter's choice.
- At times, he can be a bit overconfident.
- Leo's T-Phone ID lists him as "Leo Ichiban Turtle". "Ichiban" is Japanese for "The First" or "The Best".
- This version shows Leo's more teenage side because in previous incarnations in this franchise, Leo's personality was a more of a grown-up part. Like all the Turtles in this incarnation, he's been given emphasise on being a teenager; he sometimes lacks confidence in his position as leader, is more cocky, and seems to think less of Donnie and Mikey's fighting skills (although he is proven wrong).
- The blue in his bandana represents his main emotions: calmness and leadership.
- He is the first of the turtles to punch Splinter.
- He is the first of the turtles to call Splinter by his human name and "Father".
- He is named after the famous Renaissance master, Leonardo da Vinci.
- He seems to be the most educated out of all the brothers.
- He seems to have a fluency in Japanese.
- In Italian, Leonardo's name means "Strong as the Lion/Lion-Bold".
- Leo's swords, whilst being refered to as "Katana", are actually "Ninjatō" (忍者刀 ninjatō), (also known as ninjaken (忍者剣) or shinobigatana (忍刀)).
- He uses chopsticks correctly and deftly
- He is the only Turtle who has not yet said, "Booyakasha".
- He is the second tallest of his brothers.