He was born Giovanni Oldrati (or Oldradi) in the town of Meda, Lombardy.

Receiving a vision of the Virgin Mary, in 1134 he felt called to join the Humiliati at their Abbey of Viboldone.

This was a religious movement widely viewed with suspicion for heresy, due to their communities being composed of families as well as men and women following the monastic form of life, with the former being the leaders of the community.

Later, John went on to found other monasteries of the Order in the regions of Milan and Lombardy.

He spent his later life serving as an abbot, and is known for introducing the Little Office of Our Lady.