Priestley was educated at Dartford Grammar School.
After attending West Kent College and studying Motor Vehicle Technology, Priestley worked as an apprentice race mechanic for a series of small motor sport teams in London, working with Caterham Seven cars. After progressing and becoming lead mechanic on his team's GT3 sports car he moved into single seater racing with Lanan Racing's Formula Ford project. British Formula 3 followed with the Speedsport team, based at Silverstone, before taking the chief mechanic role at Orbit Motorsport on their Formula 3000 team.
Priestley was hired by McLaren in 2000 as a test team mechanic and quickly rose through the ranks, becoming No. 1 mechanic on the race team. He was part of the team that won the F1 World Championship with Hamilton at the 2008 Brazilian Grand Prix.
Priestley left the team in 2009 to pursue a media career and began writing about the sport for various magazines and websites and provided previews and analysis of Grand Prix for TalkSport Radio amongst other international radio networks. In 2012 he joined Jennie Gow as pitlane reporter for BBC Radio 5 Live at the 2012 British Grand Prix.
Although continuing to write for many Formula One (F1) websites, as well as contributing articles for Autosport and F1 Racing magazines, Priestley began appearing as a guest on Sky Sports News and on the Sky Sports F1 Channel's dedicated studio show, The F1 Show. He also wrote many articles about his time at McLaren for his own website, f1elvis.com.
In 2014, Priestley signed a deal to present the technical side of an F1-based series for CNBC, called One Second in F1 Racing. The series looked at all aspects of Formula One, with Priestley explaining the complexities of the cars, covering things like aerodynamics, pit stops, electronics, and tyres, and a special on the future of materials in the sport, particularly taking a look into graphene and its potential uses.
That year also saw Priestley join up once again with Jennie Gow, to front the new FIA Formula E series, broadcast live on ITV4
Priestley spent much of 2015 filming a new factual entertainment series for the Discovery Channel. The show follows him around the world, uncovering some of the craziest types of motorsport and joining existing teams to add his unique F1 experience, building a new vehicle to take part in races and competitions. The six-part series will air in 2016 in 220 different countries and will be called either Driving Wild or Gears, Grease and Glory depending on each broadcast territory.
For 2016 Priestley will be a regular guest and share presenting duties with Natalie Pinkham on Sky Sports' F1 Report Show on the Wednesday before and after each Grand Prix. He'll also attend races with Sky Sports F1 HD.