A native of Tasmania, Cadby began competing in Darts Players Australia (DPA) events in 2016 after relocating to Melbourne.
[1] He won seven events during his debut season on the DPA Australian Grand Prix circuit, and finished first in the rankings, thus securing qualification for the 2017 PDC World Championship.
[5] In October, Cadby qualified for the final of the PDC World Youth Championship, defeating Dimitri Van den Bergh in the semi-finals.
[9] On 10 February 2018, Cadby won his first PDC title since winning his tour card the previous month in the 5th UK Open qualifier, defeating reigning World Champion Rob Cross in the final with an average of 108.77.
[10] In 2019, Cadby made his PDC European Tour debut at the 2019 Czech Darts Open, defeating Wessel Nijman, Michael Smith and losing to Mervyn King.