Pokemon professors are a longstanding tradition of the series, started way back in the first generation with Professor Oak. He was such an important character to both the game and the anime as he because responsible for providing new trainers with their first Pokemon. This role is rather consistently held by the Pokemon professors of each generation, though some exceptions exist.
Usually named after trees, the professors are important supporting characters in each generation to varying degrees. Whether or not they are good at actually being professors, though, is another question entirely.
10 Professor Kukui
As the professor of the Alola games, Kukui definitely appears to take a more casual approach to his profession. His research seems to be based around Pokemon moves, with a special interest in Z-Moves, which are important in the region of Alola.
While tangentially related to his area of research, Professor Kukui sure does spend a lot of time battling. And it's not exactly scientific in its approach — whether he's building up a new Pokemon League as a pet project or masquerading as a masked wrestler to take part in the Battle Royale, there simply aren't enough hours in the day to do any teaching.
9 Professor Sycamore
Professor Augustine Sycamore is one of the few Professors to be given a first name, and he's the regional Professor of Kalos. His specialty is Mega Evolution, and he not only explains this to you but provides you with a Kantonian starter of your choosing!
It's also notable that Sycamore isn't the one to give you your first Pokemon in the Generation VI games, relegating that important task to another child. Overall, Sycamore doesn't really feature much at all during Generation VI and may find being a ladies' man more appealing than imparting knowledge to the youth.
8 Professor Sonia
The youngest Professor of the bunch, Sonia moves into her position in the post-game of Sword and Shield. Taking over from Professor Magnolia, Sonia becomes the first Pokémon Professor to specialize in something that isn't Pokemon — history (though that history is rather entwined with the phenomenon of Dynamax).
While she shows off her chops throughout the game by informing the player about many aspects of Galar's rich cultural history, there is no doubt that she's the freshest Professor. This does mean that she's probably more up-to-date on pedagogical theories than other Professors, though.
7 Professor Birch
Hoenn is the home of Professor Birch, and probably no player will forget the chaotic prologue of the Generation III games, which feature the blundering Professor being attacked by a common Pokémon. Despite his apparent ineptitude, Professor Birch seems to have some hidden depth.
While he doesn't play a large role, his son or daughter does. They become your rival for the first half of the game and through their dialogue, it's obvious that we never get to see it, but Professor Birch is very good at teaching. Brendan or May are very knowledgeable and passionate about the world of Pokemon, something that's likely a result of their father's tutelage.
6 Professor Magnolia
Before Sonia takes over, Professor Magnolia is the resident professor in the region of Galar. She naturally studies the phenomenon of Dynamax and is eager to share her findings with the player.
She is introduced as the woman who set both Leon and Sonia off on their journeys throughout Galar. They both turned out exceptionally well so we can assume that she has a natural instinct for what she does, and this is only proved further when Hop and the player character rise to the occasion, too. We don't see much evidence of her teaching style, but we can safely assume good things.
5 Professor Rowan
Studying Pokemon evolution, Professor Rowan takes up office in the region of Sinnoh. In a situation slightly reminiscent of the beginning of Generation III's games, it is through Rowan that you'll accidentally acquire your first Pokémon.
Rowan's background is that of an active researcher and teacher. During the games, he has recently come back from some years of researching alongside Professor Oak. Add this to the fact that his student (Dawn or Lucas, depending on what gender the player picks for themselves) is a passionate researcher-in-training and it seems that Rowan is an experienced hand.
4 Professor Elm
The unlucky Professor Elm has a lab in New Bark Town in the region of Johto. His area of research is Pokemon breeding, and this is exemplified early on in his discussions with Mr. Pokémon.
He almost takes the player under his wing, giving them a starter Pokemon and eventually entrusting them with a Pokemon Egg which will hatch a Togepi. He keeps in touch with the player regularly and sees the value of field research, showing that he has a keen grasp on scientific method.
3 Professor Mirror
Debuting in New Pokemon Snap, which takes place in the Lental Region, Professor Mirror is a researcher specializing in Pokemon ecology. During the game, he will send you on various expeditions to observe Pokemon up close.
His research seems to value practical experience, which is vital in the world of academia. In addition to that, he works in an engaging environment and knows when to defer to other experts in his field, such as Todd. It's obvious that Professor Mirror takes to teaching like a Ducklett to water.
2 Professor Juniper
Professor Juniper lives in the Unova region and studies Pokemons' origins. Like many other Professors, she gifts you with your first Pokemon in her game — but also gifts Pokemon to two rivals.
As a teacher and researcher, it's obvious that Juniper cares a lot. She not only teaches you how to catch Pokemon but instructs you to visit her colleague Professor Fennel, a specialist in dreams. Her multidisciplinary approach to science is refreshing and would be engaging for any of her students.
1 Professor Oak
Now, for the one who began it all. Professor Oak resides in Pallet Town but can be found in many other regions throughout the Pokemon games. He pops up in Johto to liaise with other Pokemon scientists, mentors Todd in Pokemon ecology on Pokemon Island, and even takes time off from a break in Sinnoh to show off new technology to the player.
Despite technically being Professor Rowan's junior, Professor Oak trumps him in his passion for imparting knowledge. No other Professor has a syndicated radio show purely for the purpose of teaching people about Pokemon! His methods are exhaustive and thorough, and he makes a great role model for any aspiring Pokemon researcher.