Much of Vetranio’s early life is unknown but he served much time in the military and was an experienced soldier when approached by the sister of Constantius II, Constantina, and asked to nominate himself as Caesar in 350.
Her eldest brother Constantine I had been killed while battling with his brother Constans over land and power, Constans had been killed by the usurper Magnentius and Constantius was about to battle with Magnentius. Her reasons for approaching Vetranio were probably for increased support for her remaining brother and protection for what was left of their family. Constantius at first accepted Vetranio as Caesar but changed his mind soon after and stripped him of the title. Vetranio was granted a state pension for the rest of his life and permitted to live as a private citizen, in 360 however, it is thought that he committed suicide.