Just for people to understand Casey he got his start in the early 2000's as already been pointed out. Him an his brother put together a show for HBO in 2005. None of his previous efforts created the success he has achieved as YouTube has created.
He graduated from high school an decided to skip college an moved to New York to get a job. He started to experiment with video spurred on by his brother''s own interests in video.
It was there that HBO decided to work him an his brother to produce their own short lived show. He did some commercial work for Mercedes that I believe inspired him to go the social media route.
The commercial he did for Mercedes resembles many of his videos today. Constantly moving rapid changes in camera angles an riding a skateboard.
He also does narration during the video. His entry in YouTube space hit with a thud he only took off when he went with a daily blog.
His popularity allowed him to gain advertisers such Samsung, Mercedes, Emirates air an a few others. Having produce social media content that blends his regular content with ads almost transparently.