He might not be a blockbuster movie superstar, but he does have the most subscribed YouTube channel (5mio subs) and he won GQ man of the year. For doing 10min vlogs.
He kind of moved from the inside to the outside. Before he was on youtube he was shooting movies and had his HBO series. Even now he's still shooting commercials and appearing in them. Youtube brought him a lot of recognition but he wasn't doing too bad before it either.