Who wrote Acts? The book itself does not say, as it is anonymous. However, numerous early Christians (e.g., Irenaeus, Clement of Alexandria, Tertullian, Eusebius, and Jerome) claim that Luke is the author of Acts. Anytime the Christian tradition speaks with this level of clarity, we need to listen. Christians have universally understood the author of Acts to be Luke; we should, too.
Who was Luke? Though we do not know a lot about him, Paul speaks of Luke in three different places. In Phlm 24, Paul refers to Luke as a “fellow worker.” In 2 Tim 4:11, Paul states that Luke was his sole companion during his imprisonment. And in Col 4:14, Paul calls Luke a “physician.” In other words, Luke did not make his living as a pastor. He was a doctor, not a clergyman.
What did Luke do for Christ? A lot. He wrote both Luke and Acts. These two books account for 27.5% of the NT. In fact, Luke was the most prolific NT author. He wrote more than both Paul (who wrote 23% of the NT) and John (who wrote 20% of the NT).
What does this mean for you? Most people will not make their living as pastors. Most people will make their living as Luke did by having non-ministerial jobs. How you make money ought not to determine the impact you have for Christ in the world. Be like Luke. Make money in whatever way God has called you and use your giftings to conquer the world for Christ. God uses pastors and non-pastors to accomplish his will in this world. Sometimes, even, God uses non-pastors to make the greatest impact for Christ.