At age 19 on 27 March 2006, Lester posted his first YouTube vlog titled "Phil's Video Blog" on his main YouTube channel, AmazingPhil. Since then he has posted over 200 videos on his channel and as of May 2017 has over 4.2 million subscribers and 520 million video views. He reached 1 million YouTube subscribers on 6 July 2013, 2 million on 29 August 2014, 3 million on 12 October 2015, and 4 million on 14 March 2017.
Lester has lived with best friend and fellow YouTuber Daniel Howell since August 2011, first in Manchester before moving to London together in July 2012. They have shared a total of three homes and frequently appear in each other's videos. 
Relation with Little Mix
- Phil, together with his best friend and roommate Dan Howell, hosted several events Little Mix attended, the BBC Radio 1's Big Weekend, the Teen Awards 2013 and the BRIT Awards 2015. He and Howell also interviewed Little Mix numerous of times.