In August 1997, Rennie was named as the referee for a Premier League game between Derby County and AFC Wimbledon and made history as the division's first ever black referee. He went on to officiate over 300 top-flight games across 11 years, as well as refereeing domestic cup finals and European clashes. After retiring in 2008, Rennie went on to be a mentor and sought to improve diversity within the sport. He was then set to become chancellor of Sheffield Hallam University before, on holiday in Turkey in 2024, he was diagnosed with a rare neurological condition that left him paralysed from the waist down. Undeterred, Rennie began the role last month.
The tragic announcement of his death has prompted widespread tributes from across the footballing world.