Dempsey has risen through the ranks of Australian Rugby after his schooling at Riverview College in Sydney, he represented Australian Schoolboys in 2012 before the Australia U20s in 2014.
Dempsey was selected in the Australian Under 20s team that contested the IRB Junior World Cup in New Zealand, impressing many as part of the run-on side. He also accompanied the NSW Waratahs Sevens side that played in World Club Sevens tournaments in Ireland and London in 2014.
Dempsey’s debut for the Waratahs came in 2015 when he was named on the bench for the R14 clash against the Sharks. Having impressed the coaches in his games and at training, Dempsey was elevated from the supplementary squad to the core playing squad for 2016.
Shortly after being called up as one of four development players to join the Wallabies in the 2016 Spring Tour of Europe, Dempsey re-signed with the Waratahs for a further two seasons, having joined the side in 2015.
In May 2017 Dempsey earned his first call-up into the Wallaby squad ahead of their June internationals against Scotland, Fiji and Italy.
Dempsey made his Test debut off the bench against Italy and by the end of the Super Rugby season, he had taken his total amount of Super Rugby caps to 21.
The flanker took his test cap tally to 6 before suffering an injury that saw him miss the entire 2018 Super Rugby season.
He returned to action with the Sydney Rays in the NRC and fought his way back into Wallaby contention.
He was named in the 2019 World Cup Squad with 11 caps to his name
|2015 - present|
|2017 - present|
|North Harbour Rays
|2014 - 2015|
|2016 - 2019|