In Fossil Fools, Professor Oak mentioned that, at the age of six, he decided to become a Pokémon Professor after seeing the spirals of an Omanyte shell during a school excursion to a museum.
In Will the Real Oak Please Stand Up?, Professor Oak mentioned that his childhood nickname was "Flying Finger Sammy" because he was particularly good at playing video games.
At some point Oak was a lecturer at Celadon University, where Foster was one of his top students. In Professor Elm's debut, he mentioned that he was one of Oak's top performing students at university. In Spell of the Unown: Entei, it was revealed that Oak also taught Spencer Hale and Ash's mother Delia.
Professor Oak made his debut in Pokémon, I Choose You!, appearing on a late night television show explaining the three starter Pokémon that Pokémon Trainers would receive. The next day, three Trainers from Pallet Town, including his grandson, Gary Oak, came to his lab, ready to become Pokémon Trainers. Oak gave them each a starter Pokémon, including giving Gary his Squirtle, though this wasn't revealed until much later in the series. Later that same day, Ash came to him as he was also starting his Pokémon journey and needed his first Pokémon. But because he was so late, the only Pokémon that Oak had left was a rebellious Pikachu.
He appeared again in Pokémon Emergency where he called the Viridian City Pokémon Center after hearing that Ash had already made it there from his mother. He stated how he was surprised that he had made it that far, and expressed doubts he had when Ash first left. Mentioning making a bet of a million dollars with Gary that Ash hadn't captured any new Pokémon, he was disappointed to hear that this was indeed true and he had lost the bet with his grandson. When Ash told him that he had seen an unknown Pokémon, which resembled the stone carving above him, he waved it away as nonsense, saying that Trainers have searched their whole lives for that Pokémon, and none have succeeded.
Over the course of Ash and Gary's journeys, Professor Oak took care of the Pokémon they captured that were sent to his lab. He would often gloat about how much farther ahead his grandson was to Ash like in Mystery at the Lighthouse, which often caused Ash to be extra competitive. During the Indigo Plateau Conference, Oak became greatly disappointed when he discovered that Gary had lost in the third round, but decided to look on the bright side, telling Misty and Brock that it would do Gary good to learn that "every road, no matter how smooth, has its bumps along the way". He had arrived with Ash's mother with the goal of cheering Ash on in mind.
Following the Indigo Plateau Conference, Professor Oak asked Ash to pick up a mysterious Poké Ball from his friend, Professor Ivy, who lives on Valencia Island in the Orange Archipelago. He wasn't at all surprised when Ash called him asking if he could compete in the Orange League. Though he wanted to study the GS Ball, he also wanted Ash to compete in the league so that he can get more training. During Ash's adventures in the Orange Islands, he befriended a Pokémon watcher by the name of Tracey Sketchit who was a great admirer of Professor Oak. When the group returned to Pallet Town in The Rivalry Revival, Tracey asked if he could become his assistant which Oak graciously accepted.
Not being able to discover the mystery behind the GS Ball, Professor Oak called for Ash's assistance once more and asked him to travel to the Johto region and give the Ball to his friend Kurt. He also explained that there were many new Pokémon out west which made Ash all the more eager to go and catch up with his rival, Gary. Ash completed this task in Going Apricorn!, leaving the GS Ball in Kurt’s possession for further study.
Oak reappeared in Will the Real Oak Please Stand Up?, where he and friend DJ Mary announced they were going to broadcast a live show in Maroon Town. Team Rocket got wind of this and disguised themselves as Oak and Mary. With the help of Nurse Joy, a quiz show determined who was the real Oak and Mary.
In Hatch Me If You Can, Professor Oak and Delia traveled to New Bark Town to catch up with Professor Elm, and also to see Ash before the upcoming Silver Conference. The trio’s dinner plans were interrupted after an urgent call from a nearby Pokémon Center alerted them to an issue with Ash’s newly hatched Larvitar. Oak and Elm were able to stabilize Larvitar's body temperature.
Professor Oak, along with Delia, traveled to Silver Town to watch Ash and his grandson Gary compete in the Silver League Conference, from A Claim to Flame! to Johto Photo Finish.
After learning that Ash was traveling to the Hoenn region, Professor Oak gave him an updated Pokédex and wished him the very best on his next venture.
Professor Oak made a few appearances during the Advanced Generation as well and was in a few episodes of the Weekly Pokémon Broadcasting Station's side story episodes.
In Gonna Rule the School, he was lecturing the students of Rustboro's Pokémon Trainers' School via satellite.
Oak traveled to Hoenn in A Six Pack Attack! to meet with Professor Birch for the first time and brought along the Kanto starters as they interacted with the Hoenn starters. Max was particularly excited to meet his hero in person, but the meeting was interrupted when Team Rocket kidnapped both the Hoenn and Kanto starters. Oak, May and Max followed Team Rocket to their cave headquarters and later worked together to escape the facility with the starter Pokémon.
In The Right Place and The Right Mime, Professor Oak noticed that one of his Squirtle felt most comfortable being with May, and offered it for her to raise into a strong Pokémon. He also agreed to look after her Bulbasaur after seeing that it was interested in learning from Ash's own Bulbasaur.
In The Unbeatable Lightness of Seeing!, when Ash was still recovering from his defeat at the Battle Pyramid, Professor Oak brought him a special package meant to cheer him up, containing a poster with the prints of his Pokémon, a fishing lure from Misty, and food from his mother. He also handed Ash a postcard from Gary and told him that his grandson was doing research in the Sinnoh region and that many Pokémon who live there cannot be found anywhere else. Later, he was asked to judge the impromptu Contest Battle between May and Drew. Along with Scott, he judged their battle, which ended in a victory for Drew after his Roselia and Butterfree knocked out May's Combusken and Skitty.
Ash spoke to Professor Oak regularly over the phone while he traveled through the Sinnoh region. Dawn was able to recognize him from television, but it was because of his Pokémon poetry and not his research.
In Get Your Rotom Running!, Oak suggested that Ash and his friends should visit the Old Chateau to sample its famous delicacy, the Old Gateau.
Professor Oak in the Twinleaf Festival
In Strategy Begins at Home!, Ash called Professor Oak while staying at Johanna's house and said he would be training in Twinleaf Town for a while. Oak told him to use this opportunity to learn from Johanna, as her experience as a Top Coordinator could be helpful to him. Oak also announced that he would be attending the Twinleaf Festival as a special guest.
In A Faux Oak Finish!, he traveled to Sinnoh to give a lecture on "the interrelation of Pokémon and Evolutionary stones" on the first day of the Twinleaf Festival. However, on his way to Twinleaf Town, his car got a flat tire and forced him to make a stop near a marshland. While the driver was replacing the tire, Oak decided to explore the area. He found a group of wild Pokémon who led him to a cave where a depressed Lombre was hiding. Oak found out why Lombre was so sad and gave it a Water Stone, allowing it to evolve into Ludicolo and immediately taking it out of its depressed state.
Meanwhile, in Twinleaf, James was in the town's auditorium disguised as Oak plotting to steal all of the attendees' Pokémon. When Oak arrived there, everyone in the auditorium looked confused as James insisted he was the real Professor Oak. Seeing this, a Trainer in the audience sent out his Tyranitar and asked for help, saying he was having trouble with the Armor Pokémon. James failed to figure out what was the cause of the problem and was sent blasting off by Tyranitar, but Oak was able to help the Pokémon by removing a thorn from its foot. After that, Professor Oak proceeded to give his lecture.
Professor Oak was given a major redesign in the Best Wishes series, using a different shirt collar style and wearing his lab coat above it. His hairstyle also changed, becoming more boxy. These changes make his look closely resemble his most recent game counterpart artwork.
Oak made plans to travel to the Unova region to meet with his friend, Professor Juniper, in In The Shadow of Zekrom! and invited Delia and Ash to go with him. He had since returned to Kanto as seen in Crisis from the Underground Up! where Ash called his laboratory from Nimbasa City.
In New Places... Familiar Faces!, Ash called Professor Oak to inform about his loss at the Vertress Conference. In The Fires of a Red-Hot Reunion!, the Professor appeared again in a video lecture about the Kanto starter Pokémon that was presented at the Kanto Fair, accompanied by Tracey. Later, Ash's Charizard came to his lab from the Charicific Valley so Ash would switch him for his Unfezant. Oak liked the idea of Unfezant being with him, as she could make good friends with Ash's Noctowl and Staraptor.
In To Catch a Rotom!, he appeared in the Decolore Islands, having traveled to Torom Island. Professor Oak wished to capture a Rotom to study, and eventually succeeded after helping Ash and his friends defeat Team Rocket.
As seen in Butterfree and Me!, Professor Juniper sent Ash's Pokémon caught in Unova to Oak's laboratory; Ash contacted Oak to get Leavanny sent to him to help a Caterpie evolve.
In The Dream Continues! Professor Oak was interviewed by Alexa, a reporter from the Kalos region which gave him a chance to see Pokémon from there much to his delight. He was later present when Ash announced his intention to return with Alexa to Kalos to challenge its league. As usual, Professor Oak was entrusted with the care of the Pokémon Ash had caught in Unova, as well as Charizard who would be remaining at the lab permanently from then on.
Professor Oak appeared briefly in A Battle of Aerial Mobility!, where he was introduced to Froakie before being shocked by Rotom.
He was later mentioned in Battling on Thin Ice!, where it was revealed that Ash and Serena both attended his Pokémon Summer Camp during their childhood.
In Till We Compete Again!, he joined in on a video call with Delia to Ash and his friends, where he learned Ash was going to return to Pallet Town later that day.
After winning a trip to the Alola region, Delia and Ash headed to Professor Oak's lab, where he received Ash's on-hand Pokémon and took the opportunity to entrust Delia with a Pokémon Egg. He asked her to deliver the Egg to his cousin Samson Oak, at the Pokémon School on Melemele Island.
After meeting with Delia in Alola to New Adventure!, Samson made a video call to Professor Oak and notified him the Egg arrived safely. Professor Oak did not tell Ash what Pokémon it was, so only after hatching in Getting to Know You! was it revealed to be a Vulpix, which Samson kept.
Professor Oak reappeared again in Alola, Kanto!, where Ash, his classmates, Samson, and Professor Kukui, who were all visiting Kanto, arrived at his lab to exmaine the differences between Kantonian and Alolan Pokémon. He appeared briefly in When Regions Collide! to see Kukui and his students fly back to the Alola region.
Professor Oak appeared on television in Night of a Thousand Poses!.
Professor Oak reappeared in SM111, when Ash made contact with him after discovering a group of Meltan. Rotom sent through its gathered data for Oak to examine. In the following episode, Professor Oak informed Ash that he had identified the mysterious Pokémon as an entirely new species, and he settled on the name "Meltan", the Hex Nut Pokémon and gave it a Steel-type classification.
Professor Oak in Ash & Pikachu
In the Ash & Pikachu manga
Professor Oak first appeared in Do Your Best Bulbasaur!! of the Ash & Pikachu manga.
Seen in his lab
In The Electric Tale of Pikachu manga
Professor Oak in The Electric Tale of Pikachu
Professor Oak makes a few appearances in The Electric Tale of Pikachu manga. He is a role model to Ash and is Bill's mentor. Unlike in the anime, he does not give Ash his Pikachu; in fact, he does not meet Ash until after he has already begun his Pokémon journey.
Ash meets Professor Oak for the first time in Clefairy Tale. They meet at Mt. Moon after Ash has been wandering lost in the mountains for weeks, searching for a rare Clefairy. Oak, who has been living among the Clefairy, rescues Ash and introduces him to Bill and a tribe of wild Clefairy. The three attend the tribe's evolution ceremony, after which Oak gives Ash the latest upgrade to the Pokédex for free, months before it will be available to the public.
Ash later encounters Oak again in Clefairy in Space, where he is investigating strange activity, which turned out to be caused by another group of Clefairy.
Ash encounters Oak one last time at the Pokémon Research Center in The Orange Islands, shortly before he travels to the Orange Archipelago. Here, the Professor and Bill are researching a giant Slowpoke that was found in the Pokémon Storage System.
In this canon, Oak first began his Pokémon journey when he was six years old, in which he traveled with his father (who was also a Professor) on research expeditions. During his first journey, he caught a Charmander which eventually evolved into a Charmeleon and then a Charizard.
This listing is for Professor Oak's known Pokémon in The Electric Tale of Pikachu manga.
| Professor Oak mentions that when he was a beginning Trainer, he caught a Charmander that he named Char (Japanese: ヒーくん Hi-kun). Char would later evolve into a Charmeleon and Charizard.
None of Char's moves are known.
|| Clefairy Tale
In the movie adaptations
In the I Choose You! manga
Professor Oak appeared in the manga adaptation of the 20th movie. Similar to the movie, he welcomed Ash to his lab when Ash came in late. When Ash offered to have a Squirtle, Bulbasaur, or Charmander, Professor Oak informed him that those Pokémon were already given to other Trainers. Ash saw that a Charmander was there but Cross came by and took the Charmander as he was the Trainer who picked Charmander. With no other choice, Ash was given a Pikachu from Professor Oak. Pikachu did not become fond of Ash at first as he shocked him and Professor Oak.
Gives to new Trainers
Gave away to new Trainers
In the Pocket Monsters the Movie: I Choose You! Remix manga
Professor Oak appeared in ICYR1. When Ash arrived late to his lab, Professor Oak welcomed him. He then informed Ash that the three Pokémon that he wanted were not available. As such, Ash had to choose Pikachu. Professor Oak then explained to Ash about Pikachu. However, both Ash and Pikachu got off on a rocky start since Pikachu used an Electric-type move on Ash.
Gives to new Trainers
Gave away to new Trainers