Bruno was born in Cologne of the prominent Hartenfaust family. He studied at the Cathedral school at Rheims, and on his return to Cologne about 1055, was ordained and became a Canon at St. Cunibert’s.

He later became a hermit under Abbot St. Robert of Molesmes (who later founded Citeaux) but then moved on to Grenoble with six companions in 1084. They were assigned a place for their hermitages in a desolate, mountainous, alpine area called La Grande Chartreuse. They built an oratory and individual cells, roughly followed the rule of St. Benedict, and thus began the Carthusian Order. They embraced a life of poverty, manual work, prayer, and transcribing manuscripts, though as yet they had no written rule. The fame of the group and their founder spread, and in 1090, Bruno was brought to Rome, against his wishes, by Pope Urban II.

Bruno persuaded Urban to allow him to resume his eremitical state, founded St. Mary’s at La Torre in Calabria, declined the Pope’s offer of the archbishopric of Reggio, became a close friend of Count Robert of Sicily, and remained there until his death on October 6. He wrote several commentaries on the psalms and on St. Paul’s epistles. He was never formally canonized because of the Carthusians’ aversion to public honours but Pope Leo X granted the Carthusians permission to celebrate his feast in 1514, and his name was placed on the Roman calendar in 1623. His feast day is October 6.