Within the context of what biographies were in the ancient Greco-Roman world, I would consider the Gospel of Mark to be included in those ancient biographies. While Mark’s Gospel fails to provide basic information, such as Jesus’ birth and early life, to his readers, I would argue that what Mark does inform his readers on is far more significant, which leads me to confidently identify this Gospel as a biography.
Included in Mark’s Gospel are stories of Jesus’ words and deeds, as well as his death and afterlife. Mark is packed full of instances where Jesus teaches his disciples, mostly in the form of parables. Some examples include the parable of the mustard seed, when Jesus teaches about the potential for the Kingdom of God to grow by telling his disciples about mustard plants, which they are familiar with. Jesus also performs several miracles, including healing a paralytic and a leper, and feeding a crowd of five thousand and a crowd of four thousand until they were satisfied on barely any food. Mark also includes information on Jesus’ death on the cross and his resurrection three days later.
I believe that the information provided in the Gospel of Mark clearly convinces its readers of Jesus’ significance. Why wouldn’t someone in the Greco-Roman world want to have their life saved by a man who not only heals the sick and brings the dead to life, but also raised himself from the dead? Among Jesus’ teachings, he said that everyone is welcome to follow him. In a culture that is so overcome by the effects of social classes and the prejudices and oppression that comes with them, people would want to be included in something that is available to everyone.