Lester grew up in Rawtenstall, Lancashire. Together with his older brother Martyn he attended Bacup and Rawtenstall Grammar School. He graduated from the University of York with a degree in English literature and linguistics and took a postgraduate course in the Department of Theater, Film and Television. Since 2011, he lives with his best friend Dan Howell. They lived in Manchester for a year, but have lived together since 2012 in London.
Inspired by famous channels like "Lonelygirl15", Lester uploaded his first video titled "Phil's Video Blog" on his YouTube channel AmazingPhil on March 27, 2006 at the age of 19. On March 14, 2017, its main channel reached 4 million subscribers. His second channel LessAmazingPhil, which he has been operating since 2008, cracked the 1 million subscriber mark in June 2016.
In 2010, Lester and Howell attended the annual 24-hour live internet show Stickaid, a UNICEF fundraising organization. Lester also participated in the twelve-part web series Becoming YouTube by English journalist Benjamin Cooks.
In cooperation with the YouTube channel My Damn Channel Lester and Howell created the video series Super Amazing Project in which they imagined supernatural events and discussed. Already in October 2014, both declared their work on this project as finished, to dedicate themselves to the broadcast of BBC Radio 1 from now on.
In September 2014, Lester and Howell released their first video on their gaming channel, DanAndPhilGAMES, which had 2,165,000 subscribers in May 2016. Since 2015, Lester and Howell also operate a channel called DanAndPhilCRAFTS, where they upload ironic craft videos as April Fools' Jokes on April 1 of each year. In May 2016, his channel had nearly 597,000 subscribers and 3,671,000 views.