After spending time on Planet Gurunda to recover another power sphere, BoBoiBoy's watch starts malfunctioning. It is later revealed by Ochobot that the watch had scanned the surrounding area and created a new Nature Element form for BoBoiboy to adapt to the change.
Leaf made his first debut in Episode 5, where BoBoiboy is thrown off the Space Pirate's ship and tossed into a tree. After recovering from being dropped and being hit in the head, which inadvertently caused Leaf's simpleton and scatterbrained personality, Leaf battles and ultimately overwhelms the leader of the space pirates, Captain Separo, and effectively detaining him.
He is also used by BoBoiBoy to defend the TAPOPS ship ([[Episode 6]from space mosquitoes. Leaf summons giant pitcher plants to gobble up the mosquitoes, before consequently being defeated for being the scatterbrain that he is. BoBoiBoy loses his form, but is saved by Papa Zola.
Leaf made a brief appearance in Episode 7, engaging Jokertu in combat before being defeated and forcing BoBoiBoy to flee. He did not appear as an Elemental Form when BoBoiBoy uses an Elemental Split as a card.
When being attacked by tree demons, Leaf was called out along with Earth and Lightning to save the bags of laundry that were actually secret SOS messages to TAPOPS agents in Episode 8. Leaf saved Gopal from being eaten by the tree demon before he inadvertently got in between the fight of Fang and another tree demon. As a result, Leaf was nearly devoured and stomped on, but was saved by Fang, Lightning, and Earth. He was later called upon again to save the falling laundry bags from Adu Du's mud shots.
Like the other forms, Leaf bears resemblance to BoBoiBoy. However, he is the first form who is shown having a different color shirt underneath his vest (white) than the color of his Nature emblem (emerald green) visible on the side of his hat. Leaf's hat is haphazardly worn a little sideways backward. Like all the other elemental forms, his Nature Element is also visible on the vest's zipper, but is zipped all the way up, just like Wind's.
In addition, Leaf's pupils are especially larger and shinier than all the other forms and BoBoiBoy's original persona, probably a design choice to help showcase his naivety and childish nature.
In contrast to his other forms, BoBoiBoy Leaf is much more innocent in nature, in addition to being childishly naive. He is also fairly cheeky in a childish way, often taunting and making fun of enemies when they miss an attack or Leaf bested them. However, Leaf is less level-headed and more prone to getting scared and panicking in dangerous situations, much like a young child would. Although is just as proficient in combat as the other forms, Leaf as a person can be considered a liability because of his disorganized and irresponsible air-headed nature, making him much more likely to making mistakes; having to often depend on his friends or other forms to save him if he makes one. Leaf's naivety particularly showed when he offers Captain Separo a chance to reflect on his wrongdoings, even though it's clear that the villain will do no such thing.
When first making his debut, Leaf is described as a simpleton by his friends. Furthermore, to being a scatterbrain, he is also a bit slow when it comes to taking in information and instructions. This scatterbrained demeanor is caused mostly due to BoBoiBoy hitting his head upon getting the new form. Like BoBoiBoy's original persona, he's a jokester and very playful, cheeky, maybe even more so than his original counterpart. Leaf is also fairly polite, referring to Captain Separo as 'mister' after his transformation.
Leaf is probably the embodiment of BoBoiBoy's inner child, which often has to be tucked away in favor of being the courageous and responsible superhero everyone wants.
BoBoiBoy Leaf has botanokinesis, the power to manipulate nature and plants to his will. Most of Leaf's attacks are related to using plants to help attack and defend himself.
- Leaf Shuriken (Lontaran Daun) - Leaf summons leaf-like shurikens that can be thrown at his enemies as projectiles.
- Stunning Leaf Shuriken (Lontaran Daun Kebas dan Kejang) - A variation of Leaf Shuriken. It can be used to temporarily immobilize them. This can be undone by simply plucking out the Shurikens.
- Vine Whip / Creeping Vine (Daun Menjalar) - Leaf generates a long vine that he can use to swing across a distance. It can also function like a normal rope and can be used to lasso people and objects. The vines can act like a prehensile tail, able picking things up at Leaf's command.
- Itchy Leaf Blade (Lontaran Daun Keladi Gatal) - Leaf summons a leaf-like dagger that can cause extreme itchiness stuck on an enemy. Similar to Stunning Shuriken Leaf, if removed, the effect will disappear, but effects may linger.
- Leaf Whirlwind (Pusaran Daun) - Using a whirlwind of leaves to deflect incoming projectiles, Leaf can use this ability to defend himself. This ability has a noticeable resemblance to Whirling Wind, one of BoBoiBoy Wind's ability.
- Woven Leaves (Balutan Daun) - A type of ability that uses the leaf weaving. It can be used in different scenarios and have different results.
- Woven Leaf Trap (Balutan Daun Anyaman) - Leaf sends forth strands of weaving leaves to ensnare a target.
- Woven Leaf Barrier (Daun Pelindung Mengkuang) - Leaf forms a barrier made of woven leaves to defend himself from an attack.
- Thatch Flips (Libasan Lalang) - Leaf creates a woven leaf that can be used much like a knife. This ability was used to slice HookaBot off from Captain Separo in BoBoiBoy Galaxy: Superheroes Unite (BoBoiBoy Galaxy: Adiwira Bersatu).
Abilities that BoBoiBoy Leaf has used while on his vehicle.
- Pitcher Plants Trap (Perangkap Periuk Kera) - Leaf summons large pitcher plants that can be used to devour opponents. It seems very effective against the space mosquitoes.
- Even though BoBoiBoy attained BoBoiBoy Thorn, the supposed upgraded version of Leaf in BoBoiBoy: The Movie, in BoBoiBoy Galaxy everyone refers to Leaf as a new form. It is also interesting to note that in the first episode of BoBoiBoy Galaxy, the readout of BoBoiBoy's skills by the Space Pirates showcased that he has seven elements (Earth, Lightning, Wind, Fire, Water, Nature and Solar). It is quite possible while BoBoiBoy has his Thorn form, he might have needed Leaf prior to use Thorn, which explains why Thorn is not present during Galaxy.
- Another explanation would be when BoBoiBoy does the Hepta Split after being blinded by rage after Bora Ra destroys Ochobot, he had 'forgotten' two elements (the other being Solar) until it is rediscovered and properly introduced. It's also possible that he might have lost access to these skills because he had been powered up by Ochobot and had not used it for several years (as it has been hinted that BoBoiBoy had been out of the superhero for a sum of time due to the world being at peace).
- Another theory that the upgraded power that ochobot gave him is just temporarily and gone after the fight.
- An easier explanation is that BoBoiBoy Galaxy being a soft reboot and the elemental powers are reintroduced to new audiences who have not seen the original series.
- This is the first time an elemental form's personality was directly caused by an outside force. All other elemental forms supposedly were from parts of BoBoiBoy's original persona and wasn't based on the situation. Due to blunt force trauma after falling from the Space Pirate's ship, Leaf is considered to be a bit of a dunce.
- Leaf's original personality is probably the childish part of BoBoiBoy's personality, but his simpleton nature was added when he hit his head.