Leo made his first role appearance in Pantherella as the duke to the Prince, played by Bagheera. Afterward, Leo co-starred Ash, Dawn, Brock, and Iago in Ash and the Beanstalk. He would later reappear with his partner, Benny the Beast, in Alex's Adventures With The Real Ghostbusters: The Halloween Door. Both would appear in another Halloween crossover, House of Mouse (LionKingHeart Fantasy Films Crossover) with their newest partner, Johnny (LionKingRulezAgain1).
HistoryLeo was born to King Samson and Queen Jaina (Who resemble anthropomorphic versions of Mufasa and Sarabi) in Stormwind City in Azeroth. Shortly after Leo's birth, the leaders of the 12 races Alliance and Horde blessed him and King Samsom, and the night elves, led by Malfurion Stormrage, placed a special mark on Leo's neck. It will only come on when it's purpose has been completed. Tragically on the same day that Deathwing attacked Stormwind, King Samson was murdered by the twilight's hammer cult while defending the city from the elemental invasion. Seeing that the baby was in danger, King Varian Wrynn ordered Lady Jaina Proudmoore to open a portal to Earth and told Jaina to take Leo with her. She agreed, but upon arrive, they were targeted by a hunting pack of hyenas. The previous battle had left Queen Jaina too weak to save herself, so instead she tried to save Leo. She hid the cub somewhere safe before she was killed by the vicious hyenas.
Shortly After Leo was rescued by the Autobots (Optimus Prime, Ratchet, Prowl Bulkhead, and Bumblebee), who were on patrol in Africa after they received a report of Decepticon activity. Bumblebee brought the cub back to base and Ratchet noticed a birthmark on the cub's neck. It was a dragon wrapped around a sword. Optimus, knowing the this cub could be very important, decides to bring the cub back. However, the Decepticons (Megatron, Star Scream, Blitzwing, Lugnut, and Blackarachina) attacked. They were also after the cub, so Optimus ordered Bulkhead to protect the cub at all costs. The battle ended with the Decepticons retreating.
Afterward, Ratchet decied to take a good look at the mark on the cub's neck. He tells the other autobots that he was the chosen animal who was marked and in a time of Earth and Azeroth's greatest need, he will rise and defend the two worlds. Knowing the Decepticons would destroy him, Bumblebee suggests that they find the cub a new home. On a clear night in Manhattan, the Autobots left him at the entrance of an abandoned underground research facility, now dubbed "The Labryinth," it was a home for the homeless people of the city and the domain of the Mutates (Talon, Claw, and Maggie). Leo was taken in and adopted by Talon and Maggie, and raised in the care of the Labryinth Clan in Manhattan. Despite the damp and dark surroundings, Leo learned to live with it. He enjoyed talking with the other people that he shared a home with, especially his Uncle Claw, who hadn't spoken since his transformation. Leo grew into a handsome and caring lion, and his first steps above ground gave him the sensation of opening up a whole new world.
Later on, Leo stumbled upon the El Arca big five (Xiro, Kairel, Bruma, Panthy, and Dagnino), and afterward he befriended a lonely beast named Benny. Both were entering in a film festival, but Leo felt so bad for Benny when his film was rejected that he entered the beast's film instead of his own. It was this simple act of kindness that won Leo a best friend for life. He was also introduced to the Madagascar Crew who would work with Leo and for the Alex's Adventures series.
Shortly after, Leo took Benny and the El Arca Big Five on a trip to Africa, where they met a meerkat named Timon and a warthog named Pumbaa, They also met two abandoned lion cubs named Simba and Jondugu. Leo and his friends helped Jondugu and Simba claim their rightful places in the world.
After they returned home, Leo, Benny, and Jondugu (who changed his name to Johnny) became partner film directors.
- Leo's first screen appearance was a cameo in LionheartCaptain and FantasyFilms2011's first team crossover, Sleeping Lioness.
- In Pantherella, Leo accompanied Prince Bagheera to find the girl whose foot fit the slipper. He was to ensure that the slipper remained undamaged and has performed that task despite a near circumstance.
- In Ash and the Beanstalk, Leo shows up with Kairel, Bruma, Panthy, and Leonette, all five of whom are wearing white karate outfits. Later on, he changed into clothes similar to that of Ash in the Pokemon Advanced Battle series while the girls are wearing Sailor Moon costumes.
- In their first Halloween special, Alex's Adventures With The Real Ghostbusters: The Halloween Door, Leo and Benny are arranged to join the Ghostbusters, the Alex's Adventures team, and Simba, Timon, and Pumbaa's Adventures team for Halloween.
- Leo and Benny perform a Disney style magic show in which they created everyone's desired Halloween costumes, including their own Ghostbuster's gear.
- In their second Halloween special, House of Villains (LionKingHeart Fantasy Films Crossover), Leo and Benny, along with Johnny, join Mickey Mouse in fighting the villains to take back the house of mouse.
- Leo faces of against Maleficent and defeats her using the sword Excalibur from Disney's "The Sword in the Stone."
- Leo ignites his lightsaber and pilots his X-wing fighter along side R2-D2 in the leading role as Luke Skywalker in the LionKingHeart Fantasy Films crossover, Star Roars.
- Leo is set to play two more leading roles : Robin Hood in Leo Hood and Mickey Mouse in Leo and the Beanstalk.
- Leo, Benny, and Johnny set off on their own adventure with their friends in Benny, Leo, and Johnny's Adventures of Sleeping Beauty.
- Leo is the adopted son of Talon and Maggie, the mutates from the Gargoyles series.
- Leo is currently married to Princess Aurora Rose Worgen. On December 26, 2011, they have a son named Danny.
- Leo's birth parents King Samson and Queen Jaina are revealed to be alive in Benny, Leo and Johnny's Adventures of Aladdin.
- Leo will guest star in Pooh's Adventures of Sorcerers of the Magic Kingdom.
- Leo along Benny, Johnny & Rae will guest star in Team Robot In Pokemon The Rise Of Darkrai.
- Leo along with Benny & Johnny will guest star in Pooh's Adventures of The Scorpion King.