Hailing from Aigburth, Merseyside, England, Hemmings became known for his commentary partnership with Mike Stephenson from 1988 to 2017.
He is widely recognised as "the voice of rugby league" after a career spanning over 30 years in the sport.
He and Andrew Voss are the two commentators for the video game Rugby League Live 4.
Hemmings joined satellite broadcaster BSB as the anchorman/commentator for its rugby league coverage at the network's launch in 1990.
Before this he was a Sports Reporter on the BBC regional news programme North West Tonight and was a presenter/co-presenter on the Saturday Teatime sports round-up Sport North West where he co-presented with Richard Duckenfield, Paul Craven, Andy Wyatt and sometimes presented on his own and the Friday Night BBC2 regional sports programme Sportsround and on network BBC an occasional reporter on Grandstand and Sportsnight Hemmings was the main caller for nearly all live Super League matches broadcast on Sky Sports; the two matches broadcast live each week, plus all the play-offs and Grand Final matches.