Mark's career before he started his youtube career was going to be a biomedical engineer he later thought that engineering was boring and decided to quit engineering school and do what he wanted to do which was to make gaming videos, he later found a site which was Youtube and decided to make videos on there. His main channel name is Markiplier game which was then changed to just Markiplier. His sub count right now 15.000.000+ (which could be changed, a lot) he started his Youtube channel in 2012 to today. He is Associated with multiple Youtubers such as Jacksepticeye, Lordminion777,Pewdiepie,Muyskerm,Matthias,GameGrumps,Random Encounters, and Revelmode.