Hilda was born into the royal house of Northumbria, in the north of England, a great-niece of King Edwin, in years when that kingdom still worshipped the old gods. She was about thirteen when the king turned to Christ, and on Easter Day of 627 she went down to the water with Edwin and his whole court and was baptized by Paulinus, the Roman bishop who had carried the faith into the north. Then, for a long while, nothing more is told of her. She lived as a laywoman for twenty years, a princess of a Christian house, while the kingdom around her rose and fell and rose again.

When she was thirty-three, Hilda resolved to leave the world. Her sister had gone as a nun to the monastery of Chelles in Gaul, in the country that is now France, and Hilda meant to follow her there and end her days a stranger in a far land for the love of God. But Aidan, the bishop of Lindisfarne, called her home. He would not have such a woman spent abroad when the young church of the English had need of her. He settled her first with a few companions on the north bank of the river Wear, and then set her over the monastery at Hartlepool, on the same coast, and made her its abbess. She had never been trained for such work. She learned it, and those who watched her saw that the hand of God was on her.

In 657 Hilda founded a new monastery on the high cliff at Whitby, above the sea, a house of monks and nuns together under her single rule. She ordered it after the pattern of the early church, so that no one there called anything his own and all things were held in common. She required those under her to give themselves to the reading of Scripture and to good works, and she taught peace and charity above every other virtue. Her wisdom became known far beyond the cloister. In A. M. Sellar's translation, Bede, who wrote within living memory of her, records a woman "whom all that knew her called Mother, for her singular piety and grace." Ordinary people came to her for help, and so did the great, for kings and princes sought her out and took her counsel.

Then came the year that made Whitby famous. In 664 the church of Northumbria was divided over the reckoning of Easter. The Irish teachers who had first brought the gospel to the north kept the feast by one calendar and Rome kept it by another, so that a king could be keeping the joy of the resurrection while his own queen was still fasting in Lent. The great men of the church came to Hilda's monastery to settle the question. This was the Synod of Whitby, and it met in her house because hers was the house that all sides could trust. Hilda herself held to the older usage, the reckoning she had received from Aidan and the men of Iona who had taught her. But when the king ruled for the Roman calculation, and the synod with him, she bowed to it. She had lost the argument, and she kept the peace, and the church that might have broken in two stayed one.

There was in her monastery a herdsman named Caedmon, a man already old, who had never learned to sing. When the harp was passed from hand to hand at the feast and each man sang in his turn, Caedmon would rise and go out before it reached him, ashamed that he had no song. One night, having left the table and gone to the cattle byre where it was his turn to keep watch, he fell asleep, and someone stood over him in his dream and called him by name and said to him, in the same translation, "Caedmon, sing me something." He answered that he could not sing, that this was the very reason he had left the feast. But the other told him to sing all the same, to sing of the making of the world. And Caedmon, who had never in his life made a verse, opened his mouth and sang praise to God the Creator in words he had never been taught, true English poetry, the first that is remembered under a name. When he woke he still held the song, and more came. Hilda saw at once what had been given. She received him into the monastery, had the Scriptures read over to him, and he turned them one by one into song, so that the unlettered English could hear the whole story of God in their own tongue. The gift of Christian song in English was born in Hilda's house, and it was Hilda who knew it for what it was.

For the last six years of her life Hilda bore a wasting fever. It never kept her from her work. She laboured on, teaching and ordering her house and giving thanks to God in the fire of the sickness, and she taught those around her to serve God gladly in health and to thank him faithfully in trouble. She died before dawn on the seventeenth of November, in the year 680, having received the last sacraments and having charged her nuns to keep the peace of the gospel among themselves. That same night, in a sister house at Hackness thirteen miles away, a nun who lay sleeping woke to the sound of the bell that was rung when one of the sisters died, and saw the roof above her open and a great light pour in, and in the light the soul of Hilda carried up to heaven in the company of angels. No one had yet come to tell her that her mother in God was dead. The church has kept that story ever since, sure that heaven had not let Hilda go unattended, and that the God she had served through the long fever had carried her home.