Jill Pole was born in 1933, and in 1942 (2356 NT), at the age of nine, Jill was sent to an Experiment School where she was taunted and bullied because of her name and her non-conformity to the "in" crowd. She became friends with a fellow persecuted student named EustaceScrubb , and he introduced her to Narnia. One day while being chased by a group of rowdy classmates, she and Eustace escaped to Narnia through a garden gate. Instead of the moor on the other side, it had been transformed into a sunny land with singing birds and trees.
They soon came across a cliff and Jill froze when she saw how high they were. As Eustace tried to pull her away from it, he stumbled and fell over the edge. A mysterious lion appeared at her side and seemed to blow Eustace away until he was too far away to be seen. The lion soon disappeared, but Jill came across it again while looking for a stream to drink in. The lion told her that she and Eustace were brought to this magical land to locate Narnia’s missing Prince Rilian. He gives Jill four signs that will help her in her quest and introduces himself as Aslan. The signs were 1) Eustace was to meet an old and dear friend and was to greet him at once, 2) they must travel north until they find the ruined city of giants, 3) they will find written instructions of which they must carry out, and 4) they will know whoRilian is because he will be the first person to ask them to do something in Aslan's name.
Aslan carried her to Narnia on his breath and Jill was then reunited with Eustace. They missed the first sign when Eustace fails to recognize an elder Caspian and he (Caspian) sails away before they can reunite. They meet Trumpkin and are taken to Cair Paravel for the night, butGlimfeather and other owls take them away secretly so they can continue their quest. They meet up with the marshwiggle Puddleglum, who joins them on their quest, and they begin to travel North.
While traveling in the northern territory of the Giants, a lady tells them of the Gentle Giants of Harfang and directs them to the Giant's city, where the travelers go to flee a winter storm. While there, Aslan appeared to Jill in a dream and rebuked her harshly for not remembering the signs. When looking out the window, Jill sees the ruins of a great city and the words "under me" written in the pavement. She realizes that she had once again muffed two more of the signs. The three travelers make a plan to escape the Castle. However, in the mist of their escape, Jill discovers that the Giants meant to eat them during their Autumn Feast. The Gentle Giants pursued them to the ruined cited, where they escaped into a small hole, fell down an underground cliff, and were captured by gnomes. The gnomes take them to the an Underworld City, where they are to be taken to prison, but the Prince of the Underland intervenes and has them join him in his quarters.
The Prince tells them that he is under a curse and is bound for one hour a night to a silver chair. Later when he is bound in the chair and under the curse of what they all believe to be insanity, he fulfills the forth sign when he asks them to free him from the chair in the name of Aslan. They do so, and he introduces himself as PrinceRilian of Narnia. He tells them that in the current hour he is not under a spell, an that the rest the day he is. The Lady in the Green Kirtle, the Queen of Underland enters and attempts to put a spell on them which would make them forget about Narnia. This failing, she transforms into a snake and is killed. At her death, the spell of the Underworld is broken and floods rise and fire erupts in theUnderland. Jill takes control of one of the two horses the travelers use to escape.
After the travelers are able to locate the area where the Queen had been digging in hopes of breaking out into the Overworld, Jill climbs onto Puddleglum’s shoulders to see out of a crack in the dirt. She finds herself in the heart of Narnia and is rescued by a group of partying Narnians.
When Jill awakes the next morning, she finds that the prince has gone to meet his father, who has sailed back to Narnia. Jill and Eustace ride centaurs to the port and watch as Caspian is carried off the ship and is reunited with his son. Caspian dies, but Aslan resurrects him in his country. Aslan sends Jill and Eustace back to England and after being equipped with a riding crop, Jill falls upon the bullies in Experiment House and her life at school was better afterward.
In 1949 (2555 NT), at the age of 16, Jill meets with the Seven Friends of Narnia. They was surprised with a man appears to them who has a "Narnian look about him" and they agree that Jill and Eustace must go to Narnia. While on the train back to school, and "sudden jerk" throws Jill and Eustace into Narnia, where they meet the man they had seen with the other Friends of Narnia. The man introduces himself as King Tirian of Narnia and takes them to a tower. Jill, Eustace, and Tirian soon set out in disguise as Calormenes to rescue Tirian’s friend, Jewel, who was currently being held captive at Stable Hill. While Tirian dealt with the Calorman sentry, Jill decided to peek inside the stable that allegedly held Aslan. However, she only found an old donkey with a lion skin on his back. Jill took the donkey, whose name was Puzzle, back to the others. Soon after, a dwarf named Poggin joined them, and they five went back to the tower. There, Tash appeared before them and Jill hid her face in her hands. When Tash was gone, they decided to go join some other Narnians who were coming to help Tirian. However, Farsight the eagle brought the news that the Calormenes had captured Cair Paravel, and they could only turn back to Stable Hill and die trying to save Narnia. Tirian wanted Jill and Eustace to go back to their own world, but Jill bravely refused.
Once at the Stable Hill, a fight soon broke out between the Calormenes and the Narnians, which resulted in some being killed while others were thrown into the Stable. Jill fought with her other friends, but was dragged by her hair into the stable. She was surprised to find herself in a bright and glorious land. There, she met Eustace along with the other Seven Friends of Narnia. Later, Aslan appeared and Jill witnessed as he brought all the dear creatures into his land and ended Narnia forever.
Aslan led everyone into the New Narnia, and they all met up with the other Friends of Narnia. Later, Jill was told that she had died in the railway accident in England, and would be staying in the New Narnia forever.