It's Alex Clark

Alex Clark (born February 1, 1985), and known by his username on YouTube as "itsalexclark" is an American YouTuber and cartoonist who uploads videos of animations. He created his channel on December 2, 2009, but didn't begin uploading videos until the 7th. He currently has over 1.9 million subscribers nearing 2 million.

List of Subscriber Milestones

 * Alex hit 1 million subscribers on October 4, 2017.
 * Alex hit 2 million subscribers in January 2018.