It is tradition that the author of the Gospel of Mark was "John Mark" of the Scriptures. He and his family appear to have been followers of Christ from early on with Peter as his guide as comes to us from the Scriptures below.
Prayer: Lord, through the merits of St. Mark, help us to write our own gospel and be unafraid to include the good with the bad all for your glory.
When [Peter] realized [that he had been released from Herod's prison], he went to the house of Mary, the mother of John who is called Mark, where there were many people gathered in prayer. (Acts 12:12)
After Barnabas and Saul completed their relief mission, they returned to Jerusalem, taking with them John, who is called Mark. (Acts 12:25)
Aristarchus, my fellow prisoner, sends you greetings, as does Mark the cousin of Barnabas (concerning whom you have received instructions; if he comes to you, receive him)... (Colossians 4:10)
When they arrived in Salamis, they [Paul and Barnabas] proclaimed the word of God in the Jewish synagogues. They had John also as their assistant. (Acts 13:5)
After some time, Paul said to Barnabas, “Come, let us make a return visit to see how the brothers are getting on in all the cities where we proclaimed the word of the Lord.” Barnabas wanted to take with them also John, who was called Mark, but Paul insisted that they should not take with them someone who had deserted them at Pamphylia and who had not continued with them in their work. So sharp was their disagreement that they separated. Barnabas took Mark and sailed to Cyprus. (Acts 15:36-39)
It is speculated that Mark openly marked his shame in his youthful inability to hang by mentioning this small fact:
Now a young man followed him wearing nothing but a linen cloth about his body. They seized him, but he left the cloth behind and ran off naked. (Mark 14:51-52)
It appears that he eventually managed to find his mettle and Paul's forgiveness in the earlier confident forgiveness of Barnabas:
Epaphras, my fellow prisoner in Christ Jesus, greets you, as well as Mark, Aristarchus, Demas, and Luke, my co-workers. (Philemon 1:23-24)
Luke is the only one with me. Get Mark and bring him with you, for he is helpful to me in the ministry. (2 Timothy 4:11)
It also appears that he lived long enough to follow Peter and Paul to Rome then produce a Gospel that became not just the foundation for Matthew and Luke, but the foundation of the Church in Rome.