Team Rocket members: Jessie, James, and Meowth are some of the most well known Pokemon villains, but one must wonder, where do they come from?

James

"Scaredy-Cat, Goof-Ball, Whiner. One could call James of Team Rocket many things, but don't call him late for dinner! James may not be the smartest member of his team, but he never misses a meal! Along with his partner in crime, Jessie, James tries his best to capture Pikachu with wacky contraptions like giant vacuum cleaners and rubber bubble guns. Of course, Ash and the gang foil every attempt and send James and Jessie blasting off again!"
-Topps Trading Card: James of Team Rocket (HV 4)

"James loves coming up with perfect Pokemon poaching plans. Too bad his plans are perfectly pathetic. He won't give up, though - not until he shows that puny little punk Ash Ketchum who's boss."
-Pokemon Desk Calendar

James has the body of an athlete, the looks of a movie star, and a head that's too small for his brain.

In the Anime


James (Japanese: コジロウ Kojirō) is one part of of the Team Rocket trio that follows around Ash Ketchum and friends in the Pokémon anime, usually trying to steal Ash's Pikachu, but always failing.

James is mostly a comedic parody of Team Rocket characters; the 4Kids English dub in particular tends to give him a melodramatic and even campy tone. He is somewhat famous for carrying a rose, though in more recent episodes he does not display it as often. Mostly, his rose is displayed in the Team Rocket motto.
The only child of millionaires, James was forced to endure formal society while growing up. Often having to take part in numerous lessons and activities he had little to no interest in, he eventually began to grow weary of the rules and standards that appeared to be ever-present within the upper-class. At a young age, he was engaged to a girl, Jessiebelle, whom we find out in DP ep. 153 that he actually originally wanted to marry, until it quickly became obvious that she was obsessively controlling. Soon after the engagement was announced, James, not able to stand Jessiebelle's overbearing personality (to this day he remains terrified of her), ran away from home, leaving behind his beloved pet Growlie. He attempted to enroll in Pokémon Tech, a Trainer's school, but, along with his new friend Jessie, flunked out. Then, with Jessie, he joined the Sunny Town bicycle gang, where he was popular for being the only gang member to have to use training wheels (nicknamed "Trainer Jim"). Eventually James, Jessie, and the bike gang went their separate ways.
Due to conflicts in canon between Kanto and Johto episodes and the special episode Training Daze, what happened between James and Jessie after the bike gang is unknown. What is known, as shown in the special episode, is that they joined Team Rocket separately and were on initially unfriendly terms after being grouped with Meowth. However, they quickly made up and the rest is history.
James has a tendency to be swindled by a Magikarp Salesman, who, despite James's increasing wariness and personal vendetta against the shady character, has on many occasions tricked him into buying a Magikarp or other useless Pokémon and items for large sums of money.
James loves rare bottle caps and has an impressive collection of them. This hobby started when he was a young child. In the episode All That Glitters! it is revealed that he has "drunk enough soda pop to float an aircraft
carrier".
For unknown reasons, he, Jessie and Meowth mostly use hot air balloons instead of faster ways of transportation. However in newer episodes the balloon is shown with 'jets' attached to explain how they get from one place to another faster than walking.
As the standards of the Team Rocket organization dictated, James was first shown with a Poison-type Pokémon. However, James seems to have a fondness for carnivorous Grass-type Pokémon, owning Weepinbell, Victreebel, and Carnivine. It was shown during a flashback in Cream of the Croagunk Crop! how James, as a boy, found Carnivine in the Great Marsh. It was trapped in the mud and James rescued it, the two forming a bond of friendship. It is not shown how he captured Weepinbell, but he had owned it for a long period of time before its first appearance. The capture of a Cacnea early in Hoenn furthered his apparent preference for Grass-types. Often, when going into battle, his Grass Pokémon will show great affection towards James. It is also shown there is a strong bond between James and his other Pokémon; James almost treats them as his own children. This could stem from the childhood memories he occasionally brings up, where it is shown that while growing up James hadn't really had any friends other than his Pokémon. When it comes time to leave a Pokémon behind for one reason or another, James often has great difficulty in letting go of his beloved friends.
# Both Jessie and James have used a Charizard at separate times (Jessie having used two). None of the three remained in their care, however.
# James at times uses the name Jameson.
# James hasn't evolved any of his Pokémon since Here's Lookin' at You, Elekid!.
# He is one of the only main characters to, after being given his first Pokémon, at one point not have any Pokémon on hand. This was in A Poached Ego! during the brief moment after he released Weezing and before he caught Cacnea. The other character was Ash briefly when he was traveling to Hoenn.
# James is the only main character to have one Pokémon and release/give it away, then get another Pokémon of the same species.
# James and Meowth are the only main characters to have their voice actors replaced during the 4Kids run of the show, then again when Pokémon USA took over.
# James is, as of the most recent Japanese episode, the only Trainer on the main cast who has not yet owned a Generation II Pokémon during the Diamond & Pearl series. In fact, the only Generation II Pokémon James ever had was a Hoppip, though it flew away before he could put it in a Poké Ball.
# In the dub, both of James's Generation III Pokémon were given away in the second episode of a season which was recorded at a new studio from the prior. Chimecho was left in the care of Nanny and Pop-Pop in the second episode of Battle Frontier (dubbed at TAJ), while Cacnea was given to Gardenia in the the second episode of Battle Dimension (dubbed at DuArt). This is merely coincidence, however.
# James was the first main character to release a Pokémon.
# James was the first main character to be shown with both of their parents (although this would be equaled by Brock, May and Max as the series went on).
# In Bulbasaur's Mysterious Garden, James states he has "allergies" when talking about the pollen from the flowers. It is a possibility he suffers from hay fever, or something similar
In the games

Both Jessie and James appear in Pokémon Yellow as in-game bosses. They first attack the main character in Mt. Moon, while trying to take one of the rare fossils uncovered there.
Later, in Celadon City's Rocket Game Corner, Jessie and James guard Giovanni's room in the Team Rocket base. During that time, as the player runs into them, they are eager for revenge after the main character busted up their plans at Mt. Moon.
They hold Mr. Fuji hostage at Pokémon Tower. They attack the main character on the seventh floor.
Finally, at Silph Co. in Saffron City, Jessie and James make their final appearance, once again trying to stall the main character from reaching their Boss.
Unlike in the anime, Jessie and James do not follow the main character around and come up with their usual evil plans to capture Pikachu.
#

* Ironically, a running gag in the anime involves his Grass-type Pokémon hurting him in a show of affection.
# In the main series games, James and Jessie are the only characters from Generation I to appear only in that generation, as they do not reappear in Generation II and Generation IV when Kanto is revisited, and (being exclusive to Pokémon Yellow) were not adapted into the Generation III Pokémon FireRed and LeafGreen remakes.

In the TCG

Jessie and James appear on both versions of the card Here Comes Team Rocket!, which originally released in the Team Rocket set; it was re-released with different artwork in EX Team Rocket Returns. In that expansion, there was also a preconstructed Theme Deck based on James.
It is rumored that James may also be on the Gym Challenge set card Rocket's Secret Experiment, as there is a Rocket in the background, seen only from the back, who has his hairstyle, but what he may be doing in the lab is left to the imagination.