Digory Kirke, as a young boy, originally enters Narnia by the power of the magic rings his uncle had created. However, before hand, he and his childhood friend, Polly, enter the Wood between the Worlds, where they decide to explore. After entering a pool and accidentally bringing Jadis from a different world back into the Wood between the Worlds, Kirke and Polly return home. However, their "friend" wrecks havoc on England, causing the two to return to the Wood between the Worlds with several other companions. It is from here that they enter Narnia, and witness Aslanís creation of it. Because Kirke brought evil into Narnia in the form of Jadis, Aslan asks him to make a special journey to retrieve an apple that would protect the fledgling nation. After his return, he plants the apple, which grows into a great tree. Eventually, Aslan gives Kirke one of the apples from the tree, and he and Polly return to England. Once they return, Kirke gives the apple to his ailing mother, who revives.
The next day, Kirke and Polly take the rings Kirkeís uncle had made, and bury them around the core of the apple. The core sprouts, and a Narnian tree grows. Unfortunately, many years later, the tree blows over in a storm, and Kirke, who has grown up and was now a professor, has it made into a wardrobe. This wardrobe is the same one that, when the Pevensie children hide in it, transports them to Narnia while they are staying at Kirkeís house. Professor Kirke had opened his home to children who needed to move away from the cities for safety reasons during the war. This visit evidently lays the foundation of a strong friendship, as he later guides and councils Peter and Susan.
Once Peter is older, he goes to stay with the professor and study under his tutelage. Unfortunately, Kirke no longer has his large house, so Lucy and Edmund cannot accompany Peter, although Kirke would be very glad to have them, and it is for this reason that they must spend a summer with their lovely cousin Eustace. In the Last Battle, when the three Pevensies and Polly vist, the foursome and Kirke see a vision of King Tirian. Realizing that Narnia is in trouble, the idea to retrieve the magic rings is mentioned, and Kirke goes to get them. However, the rings are never used, as all involved die in a train wreck, but find themselves forever in Aslanís Country.