Neptune first appears at the beginning of the short sitting on his throne on the ocean floor, singing as he celebrates with his subjects. When a giant clamshell is brought before him and opens to reveal his daughters, he playfully taunts them by tugging at their hair and laughs as they tickle his toes. Later, when a ship full of unruly pirates arrives and the crew sucessfully captures one of the girls, Neptune is unable to help her at first because the pirates drop their anchor near him, resulting in the chains weighing him down. However, after a brief struggle, he sucessfully pulls apart the chains and rises to the surface to deal with the pirates, first by stabbing their ship with his trident, then by stirring up a whirlpool which sends the ship spinning away, never to be seen again.
Neptune appears when a shrunken Mickey is leaping across the land masses on a globe in order to escape from the King of Hearts' guards. After Mickey accidentally misses a land mass and falls into the water, Neptune rises up from under him and stabs the mouse's rear end with his trident, sending him flying off of the globe while looking after him dissaprovingly.
Neptune makes a very brief appearance in The Cold-Blooded Penguin segment when Pablo arrives at the Equator. In order to help the penguin cross it, Neptune rises up from underneath it and lifts it up with his trident. He looks slightly different then he did in his his two previous appearances, as he is seen wearing a green smock and blue trousers.
The Seven Dwarves and the Pirate
In this comic story, Neptune is breifly seen.
King Neptune is briefly mentioned in the episode "Undersea Bucky!" While surfing the waves aboard Buckey Jake and his crew spot Marina in a rush with her dolphin friends informing Jake and crew underwater mermaid city of legend Neptune City has gone dark and the puny pirates offer help. Bucky revels to the crew the ability to transforming into a submarine allowing young pirates to follow Marina beneath the waves, on there way to the mermaid city Jake and his crew past by a large statue of King Neptune which is said to hold a large magical Pink Pearl that light up the city.
In the episode "Izzy's Trident Treasure", Marina and Stormy come to Pirate Island to needing the assistance of Jake and his crew. Stormy explains to them that she found a map to Neptune's Trident. It located on a mountain that is in the desert. Sense mermaids can't walk on land they can retrieve the trident. Izzy offers her assistants being an honorary mermaid, she can touch the trident.
King Neptune is briefly mentioned in the episode "Cubby's Pet Problem", Stormy's help guide Jake and his crew find the Cave of Neptune. Stormy heard legends say that an amazing sea creature lives there, but no one's ever seen it. As Jake and friends follow Stormy in there Sea Scuttlers they pass by the giant statue of King Neptune.
King Neptune's statue makes a brief appearance in the special episode "Jake's Never Land Rescue",Jake follows the magical ball of light sent by The Guardian to Mermaid Lagoon, Jake learns from Marina and Stormy, that the magical ink from the Golden Squid will restore Cubby's map. While Jake is being chased by the squid Neptune City can be spotted. After retrieving the ink and continuing his quest to save Never Land from vanishing Neptune City vanishes. Neptune City later reappears once a new Forever Tree grows and Never Land is saved.
King Neptune's statue makes a brief in the episode "Jake's Royal Rescue", while Queen Coralie is held captive by Captain Hook and his scurvy crew. Queen Coralie sings a song about her kingdom Smee, Sharky and Bones envision what it may look like.
King Neptune first appeared in the episode "The Great Never Sea Conquest". When the evil Mer-wizard named Lord Fathom is released from an underwater prison, he sets out to take over the Never Sea. Lord Fathom tricks the mermaid in revealing the location of the Dark Light Emerald the source of Lord Fathom's power. Lord Fathom releases the Strake and places it under his control and a battle erupts. King Neptune appears and tells Jake that all he needs to defeat Fathom and the Strake is to believe in himself. Using the powers of his sword, Jake finally defeats Fathom and the Strake. He then re-imprisons the Strake and destroys the DarkLight Emerald, freeing Queen Coralie, Marina, Stormy, and the sea creatures and send Fathom packing.
King Neptune is briefly mentioned in the episode special "The Legion of Pirate Villains!", Jake and his crew meet Captain Colossus who is slowly losing his strength still not recovering his strength from his first battle with the Strake. And in his weaken state couldn't recover the Treasure Keys to his treasure bestowed upon him by King Neptune that will restore his strength.
Neptune in King Neptune is seen as a rather cruel tyrant, not necessarily kind or generous. He seems rather absent-minded in The Seven Dwarves and the Pirate, and jolly in The Three Cabelleros.