Illingworth won the 2014 Australian Chess Championship in Springvale, Victoria with a score of 8/11. He scored 6½/9 for Australia at the 2014 Chess Olympiad in Tromsø. The next month, he achieved his second grandmaster norm at the First Saturday GM tournament of September 2014, where he took first place. Strong domestic results include winning the 2014 MCC Hjorth Open with a score of 9/9 and shared second place with Murtas Kazhgaleyev in the 2015 Australian Open. Illingworth won the 2015 Oceania zonal championship after a playoff match against Brodie McClymont. As a result, he qualified to play in the FIDE World Cup. In January 2017 Illingworth won the Australian Open Championship in Brisbane. He won the Oceania zonal again in 2019, held in Guam.