Jessie grew up as the daughter of Miyamoto, a high-ranking Team Rocket agent. She developed a crush on a boy at her school, Astin. She enrolled in dancing and Astin asked her if she wanted to come with him on his journey as a Pokémon Coordinator, but because Jessie's day view was days away, she stayed at school to practise and then on that day of her day view, her two friends passed, but she didn't. Worse, Miyamoto disappeared while at the Andes Mountain attempting to record the voice of the Legendary PokémonMew and Jessie was forced to live in a foster home with little money and had to eat snow.
She then attempted to enroll in Pokémon Nurse School in Johto, which was intended for Chansey. She was quite skilled a things such as bandaging, and even showed a Chansey how to do it, which she quickly became good friends with. However, because she was not a Chansey, Jessie couldn't do things like use Sing to soothe Pokémon, instead falling asleep herself. Ultimately she failed to graduate, and on graduation day she simply packed a bag and left. As she was leaving, Chansey came up to her and offered her her nurses' hat, but Jessie refused to take it. Chansey then broke her egg-shaped pendant she got as proof of graduating in half and gave one half to Jessie so that they would have something to remember each other by.
She then attempted to enroll in Pokémon Tech, where she met James. They both flunked out and then together joined a Bicycle gang on a bridge in Sunny Town. She eventually went seperate ways with the bicycle gang and James and then took various other jobs. In the bike gang, she was known for swinging a chain above her head as she rode her bike, acquiring the nickname "Chainer Jess".
She was supposedly a model at one point and also worked at a t.v. station as a weathergirl. She also trained as a ninja. She also visited the Hoenn region once and got a Contest Pass, because she wanted to find Astin.
Jessie then became a member of Team Rocket like her mother before her. However, Jessie kept advancing after disqualifying every partner and Pokémon she gained, which lead Drill Seargent Viper to feel she should be thrown out. She also developed a rivalry with fellow member Cassidy and later Wendy for failing to pay for a drink (making Wendy pay). She was later partnered up with James and they were later joined by Meowth.
The trio then entered in a test across a landscape and James promised Jessie to never let her down, which eventually resulted in James getting injured and leaving Jessie and Meowth by themselves. James then joined up with them again for the final test for a real-live break-in to steal the Red Snorlax. They almost succeeded before Viper cut them off, revealing it was another test. They graduated and became the Team Rocket trio. Jessie also recieved an Ekans for her birthday.
The trio follows Ash to the Orange Archipelago and later to Johto, where Jessie runs into the Chansey from her childhood, now evolved into a Blissey. Jessie aided it when Nurse Joy accuses it of stealing food after it gives it to them. Jessie also accidently trades her Lickitung for a Wobbuffet that often pops out of its Poké Ball.
The trio follows Ash to Hoenn, where Jessie starts competing in Contests. In doing so, she releases her Arbok to go with some Ekans, but later captures a Seviper. Wanting a Beautifly, she catches a Wurmple, but it decides to evolve into a Cascoon and then a Dustox instead of a Silcoon without Jessie realizing this. However, when she does, she is overjoyed. She ends up losing every contest without a single Ribbon.
Giovanni orders the trio to head to Antartaca, but after seeing Cassidy and Butch with new gadgets, they stay in Kanto and improve their motto. They then continue to follow Ash around and despite her losses in Hoenn, Jessie competes in Kanto contests disguised as Jessibella (Japanese: ムサぴょんMusa-pyon) wearing a red dress and glasses. She continues her losing streak and the group finds out who she really is in the last contest, but later disguises herself as Jessadia (Japanese: プリティ・ムサリンPretty Musalin) and wore glasses, long white socks, a yellow and orange dress, and had her hair in pigtails. Harley temporarily aids her by giving her his Pokémon. He asks her to go with him to Johto, but she declines.
In Sinnoh, Jessie retains her love for contests once again. She disguises herself as Jessilina (Japanese: キャンディ・ムサリーナCandy Musalina), using big glasses and an orange dress. In these series, she actually wins contests, winning the Solaceon Ribbon with her Dustox. However, she later releases it to be with Austin's Dustox because she doesn't want Dustox to suffer the way she did long ago. She loses the first round of the Wallace Cup, but later uses her Jessadia disguise again to interview the contestants. A while after, she catches a Yanma and sends it to Giovanni. She keeps it and it evolves into Yanmega after Giovanni rejects it.
In the Best Wishes series, they become more serious and less goofy. Giovanni sends them to Unova for a mission involving the Meteonite and they just happen to run into Ash on the way. They then decide to capture Pikachu and Zekrom after seeing it. Jessie captures a Woobat and they steal a meteorite from the Nacrene Museum, which them to the Meteonite in the Desert Resort. However, during Ash's inteference along with Team Plasma, events lead the project to be closed off and Matori informs them that they will not be needed for any more missions and their tasks are up to them.
Wobbuffet was obtained by Jessie in an accidental Trade with Benny. It cannot do anything, but has a powerful Counter move that reflects attacks at its opponents with double the power. Jessie left it at Team Rocket HQ to keep attention from being attracted to Team Rocket in Unova.
Seviper was captured by Jessie in A Tail with a Twist, because she was impressed of how it beat Ash's Treecko. She weakened it after she was enraged of it biting her hair and used made-up Fury Swipes and Mega Kick. Seviper then became Jessie's main battling Pokémon, with powerful attacks at its disposal such as Bite and Poison Tail. She left Seviper at Team Rocket HQ because it was not native to Unova and they would attract too much attention if they used Pokémon not native from Unova.
Yanmega was captured by Jessie as a Yanma. It was swiped from Tyler after he attempted to catch it for three days and sent it to Giovanni. However, due to Yanma not being very good, he sent it back to Jessie and it evolved into Yanmega because of it knowing Ancient Power.
Yanmega was revealed to be a girl when Evil Togepi attempted to use Attract on her and it failed. Jessie left her at Team Rocket HQ because Yanmega was not native to Unova and using it in Unova would attract too much attention.
Dustox was captured by Jessie as a Wurmple because she wanted a Beautifly. It evolved into a Cascoon, but she believed it was a Silcoon and forced it to evolved into Dustox, which she enjoyed.
Dustox was one of Jessie's main battling Pokémon until Sinnoh, where Dustox fell in love with Austin's Dustox and Jessie released it because she didn't want it to miss the chance of love like she did with Astin. She left it at Dustox Crossing.