Peter lived in London, England, trying his best to protect his younger siblings and to act like a responsible young adult. When evacuated to the countryside with his brother and sisters by train because of the air-raids of World War II, he and his three siblings stayed at the old mansion of Professor Digory Kirke until the end of the war.
When his youngest sister, Lucy, first stumbled upon the Wardrobe leading to the World of Narnia, Peter did not believe her until he and the other Pevensies entered the Wardrobe themselves. He later apologized to Lucy for not believing her and became angry at Edmund for earlier denying Narnia's existence when he had also been there previously.
Peter and Susan agreed on letting Lucy decide what to do next and she wanted them all to meet Mr. Tumnus. When they arrived at Tumnus' house they found it completely destroyed and Mr. Tumnus arrested by the orders of the White Witch for being with a human (Lucy) and not turning her in. Lucy is devastated and while Susan wants to leave, she says that they cannot leave Mr. Tumnus.
Outside Mr. Tumnus' home, they are found by a talking Beaver who tells them that he knows Tumnus and then brings them home to his dam. There he tells them of the story of the White Witch, Aslan and the Prophecy. Both Susan and Peter are concerned about the war they want them to fight in and prepare to leave for home. However, they notice that Edmund is no longer in the dam, they go after only to arrive too late. Peter tries to follow his brother inside the Witch's castle but is stopped by Mr. Beaver who tells him that only Aslan can save their brother now. To which Peter responds, "Then take us to him."
As they set out for the Stone Table, where Aslan has his army, Peter receives his sword Rhindon and a shield from Father Christmas, who also tells them that winter is almost over, which meant that the ice on the river would melt. The siblings and the Beavers arrive at the Great River and find the ice to be melting slowly, they try to cross but hot on their heels is the Witch's police with the Wolf Maugrim in the lead. One wolf immobilises Mr. Beaver and Peter draws his sword to protect the others, Maugrim patronises him and tells him that if he puts his sword down and leaves Narnia with his sisters, Edmund would be allowed to leave with them. Susan, who's getting tired of all of the fighting and running tells to drop the sword and listen to Maugrim. Peter has no time to make up his mind before Lucy screams out his name and they notice that the ice on the waterfall is breaking, Peter tells his sisters to hold on and he stabs the sword down in the ice and they wait for the water to come. They make it down the river but as they come ashore Lucy is missing, Susan instantly blames Peter but Lucy is quickly found. They then continue towards Aslan's Camp.
They arrive at the camp and meet the Great Lion Aslan, whom they plead to about helping Edmund. Aslan tells them that getting Edmund back might be harder than they think. Peter later stands on a precipice looking towards Cair Paravel, Aslan comes to stand beside him and Peter confides in him about he failed his promise to his mother and how he couldn't protect his sisters and his brother. Aslan promises that he will do what he can for Edmund but that he too wants to keep his family safe and wants Peter to ensure that. Their conversation is interrupted when they hear Susan's horn, which indicates that she's in danger. Peter runs to her and finds both Susan and Lucy in a tree with wolves snapping at their feet. Peter kills of Maugrim and Aslan lets the other wolf go and tells a part of the army to follow him, that he will lead them to Edmund. Aslan tells Peter to clean his sword, he is then knighted by Aslan and gains the title Sir Peter Wolf's-Bane.
When Edmund then returns, having been found by the army that followed the wolf, Peter remains cold towards him but that quickly disappears when he smiles and tells Edmund to get some sleep. When the Witch then arrives at Aslan's Camp in and tells them that Edmund is her property and he is to die on the Stone Table, Peter steps forward with a sword in his hand to protect his brother. When the Witch then renounces the claim on Edmund's blood, Peter and his sisters hug Edmund in happiness.
On the morning of the battle, Peter is informed that Aslan is dead and he's the only one left to lead the army. Peter starts doubting his ability to lead and it isn't until Edmund tells him that Aslan believed he could and so does he that Peter pulls himself together and gives out the orders.
During the Battle of Beruna Peter was at the front line together with the centaur general, Oreius. When the battle started going downhill, Peter ordered Edmund to go and find the girls and get them home. Edmund, however, went against Peter's orders and attacked the Witch, which resulted in Edmund getting gravely wounded. Peter sees his brother go down and shouts his name before charging the Witch, he takes her on without help but can't hold up, before the Witch can deliver the last blow, Susan and Lucy arrive with Aslan and reinforcement. Aslan takes out the Witch and tells Peter that it is finished. Peter embraces his sisters before going to look for Edmund, when they find him his brother is near death, which tears Peter apart. Lucy pulls out her cordial and as soon as Edmund draws breath again Peter quickly pulls him in for a hug, which Susan and Lucy quickly join.
After the battle Peter was crowned by Aslan as High King Peter, the Magnificent, Lord of Cair Paravel, and Emperor of the Lone Islands, each of his siblings sharing the throne. The ancient prophecy of two Sons of Adam and two Daughters of Eve coming to sit on the four thrones of Narnia at the castle Cair Paravel had come to fruition. This marked the end of the Long Winter and was the beginning of Narnia's Golden Age.
One year later (1941) Peter has trouble adjusting to his life in England again, where he holds no authority and where no one listens to him. He tends to get into several fights which often ends with Edmund having to pull him out of it. As Peter and his siblings are at the train station preparing to leave for boarding school, they get sent back to Narnia. Peter and his siblings are overjoyed to be back in Narnia but soon realise that this isn't the Kingdom they left behind and that all their friends were now gone. While scouting around the area they come across two Telmarines who are trying to cast a dwarf overboard. Susan shoots at them and Peter jumps into the water in order to save the dwarf Trumpkin.
Trumpkin doubts the fact that they are the Kings and Queens of Old, but after a sparring match with Edmund, all doubt is thrown out the window. Trumpkin tells them how Narnia has changed and that the Telmarines have now invaded the country and forced the Narnians into hiding. They set out for Aslan's How, where the remaining Narnians are creating an army to fight the Telmarines. They move to cross at the River Rush only to find out that it has now become a gorge that is nearly impossible to cross. Lucy states that she sees Aslan on the other side and that he wanted them to follow him. Since Peter can't see him he tells Lucy that it could have been any lion and that they should take another way. When they find out that that way is guarded by Telmarines they decide to head back and try to cross the gorge.
They succeed and later Peter attacks a Minotaur, which is considered a fell beast, but is instead stopped by a young man who they then find out is Prince Caspian, a former Telmarine prince who escaped after his uncle Miraz tried to kill him. Caspian then leads them to Aslan's How, where the Pevensies find out that it is actually a tomb that was built over the broken Stone Table. Peter thinks that it's time to fight back against the Telmarines and suggests that they should plan an attack against the castle, Caspian disagrees and thinks that they should dig in deeper in the How. But against Caspian and Lucy's wishes they start planning an attack on the Telmarine castle.
Edmund is sent in first and as soon as he gives the signal, Peter, Susan, and Caspian fly in on griffins and take out some of the guards. Caspian then says that he wants to go a free his teacher that is locked away in the dungeons, Peter complies after Susan tells him that Caspian will still have time to get the gate open to let in the troops. But things don't go according to plan when Caspian finds out the truth about his father's death and he goes to Miraz's room to get some answers. The rest of the battle just goes downhill from there. More than half of the troops get killed and the rest head back to the How. Peter blames Caspian for the failure and Caspian blames Peter, this nearly ends in a sword fight between the two but they're stopped by Edmund.
The Telmarines are now moving closer to their camp and they now decide to send Lucy and Susan to look for Aslan while Peter and Caspian hold of the Telmarine army. In order to buy some time, Peter challenges Miraz to single combat ending with death and the winner gets a total surrender. Edmund delivers the challenge and Miraz accepts. Peter does well in the battle against Miraz until he gets his shoulder dislocated. He calls for respite and also sees Susan returning with Caspian, Peter asks her about Lucy and when he knows she got through he tells Susan to go and join the archers. Before he goes back to the combat he asks Edmund what he thinks might happen in England if you die in Narnia, he truly believes he might die and tries to tell his brother what he means to him, however, Edmund pushes his shoulder back into place and tells Peter to save it for later. Peter wounds Miraz but refuses to take his life, saying that it's not his to take. He gives a sword to Caspian but he also decides not to take his uncle's life. Miraz is then killed by one of his generals with one of Susan arrows, which make the Telmarine army believe that it was the Narnians. They attack and Peter fights together with his siblings and Caspian, later during the battle the trees arrive as reinforcement, which shows that Lucy succeeded and found Aslan. They then drive the Telmarines towards the Beruna River where they encounter Aslan and the rest of the Telmarine army is defeated by the River God.
They then have the coronation for Caspian, uniting the Narnians and the Telmarines. Later, Aslan seeks out Peter and Susan, telling them that it is their last time in Narnia and that they have to find him in England. Peter and Susan are of course sad that they won't return but accepts it. Peter later joins Aslan, his siblings, Caspian, and all the other Telmarines and Narnians in the courtyard of the Telmarines castle by a big tree which Aslan transforms to a portal to England. Peter tells his siblings that it's time to go and Edmund and Lucy learn that their older siblings will never return to Narnia which leaves them devastated. Peter tells Lucy that it will be all right and he hands over his sword Rhindon to Caspian, passing over the torch. The siblings return to England and boards the train for boarding school.
Peter is the oldest of the Pevensie siblings and feels that he is responsible for his younger siblings, he's protective of them and very caring.
Peter is depicted as a warrior-king who seeks to do the right thing at all times. He has an undying love for Aslan and recognizes him as his leader and friend. Peter saw Aslan as a father figure. Aslan explained to Peter his responsibility as a born leader and gives him the support of a father towards his son. Peter, in turn, respects all of Aslan's choices and trusts him no matter what.