Almost nothing is known about the life of Venerius before his election as bishop of Milan. According to the 5th-century historian, Paulinus, Venerius was a deacon and he was present at the death of Ambrose in 397. Venerius was elected bishop after the death of Simplician in the winter between 400 and 401. He was already bishop of Milan when he received a request by a provincial synod held on June 18, 401 at Carthage to send in North Africa some clerics from Milan. One of the clerics sent was actually Paulinus.[2]
Venerius died on May 4, 408, and he was buried in the Church of Saint Nazarius and Celsus in Milan.[3] A late tradition, with no historical basis, associates Venerius with the Milan's family of the Oldrati.