Bavo was born near Liège, Belgium, to a Frankish noble family that gave him the name Allowin. His father was Pippin of Landen, the Mayor of the Palace of Austrasia.
Wild as a youth and selfish, he was known to have sold servants to local nobles as slaves. He contracted a beneficial marriage, and had a daughter through it. He was a soldier; however, he led an undisciplined and disorderly life. Shortly after the death of his wife, Bavo decided to reform himself upon hearing a sermon preached by a monk, Saint Amand. Bavo was struck after the sermon at the emptiness of material objects and donated his wealth to the poor after he converted to Christianity at Amand's convent. Bavo traveled with Amand for some time in his missionary work through France and Flanders.
He built an abbey on his grounds and became a monk. He distributed his belongings to the poor and lived as a recluse, first in a hollow tree, later in a cell in the forest near the Abbey. He died at St. Bavo's Abbey in Ghent, in today's Belgium.