We are never told the age of Joseph or Mary. Many assume that the virgin Mary was a teenager because that was the age that young women often got married at that time. The assumption, based on practices at the time, is that Joseph would have been older than Mary, but how much older is unknown. The fact that Joseph’s parents are never mentioned in conjunction with the marriage arrangements might indicate that he is older and no longer under his parent’s authority. However, Mary’s parents are never mentioned, either, yet many still assume that Mary was a teenager when Jesus was born.
In the Roman Catholic tradition, Mary remained a perpetual virgin. When the New Testament speaks of Jesus’ brothers and sisters (Matthew 13:55–56), one Roman Catholic interpretation is that these are Joseph’s children from a previous marriage. If we assume he had multiple children from a previous marriage, then we can assume that he must have been quite a bit older than Mary—at least old enough to have had five or six other children. This assumption, however, is based on a theological presupposition about Mary’s perpetual virginity, and it is not the most natural way to understand the biblical text. Even if it were the case that Joseph was married previously, we still don’t know how old Joseph was. It is possible for a man to have several children by his mid-20s, and some men become grandfathers in their 30s.
By the time of Jesus’ public ministry, Joseph seems to have passed from the scene. Although Mary is mentioned several times in the gospels, Joseph is never mentioned after the incident of twelve-year-old Jesus in the temple (Luke 2:42–52). Joseph is not at the foot of the cross with Mary, and Jesus commits His mother to the care of His disciple John (John 19:26–27). This would have been an odd decision if Joseph were still alive. For these reasons, many assume that Joseph must have died by this time—and that is seen as further evidence that he was older than Mary. Joseph’s death is probably the most likely explanation of his absence at Mary’s side during the crucifixion; however, even if Joseph had died, we don’t know that it was from old age. There are many things that can cause a young man to die in our time and probably many, many more that could have caused it in the first century.
In the final analysis, theories about how old Joseph was when Jesus was born are speculation based on almost no evidence. We can, however, say with certainty that, if it were important for us to know, the Bible would have made it clear for us. What we do know is that Joseph was a godly man who was entrusted by God to care for Mary and her Son Jesus.