He began officiating in 2000 at local rugby clubs in Coventry before joining the elite referee development at the RFU in 2008, and was part of the touch judge team in the 2008–09 English Premiership. In 2010, Garner was part of the IRB referee panel for the 2011 IRB Junior World Championship in Italy - refereeing 4 fixtures, before refereeing the final of the 2012 IRB Junior World Championship between hosts South Africa and New Zealand.