Jeffrey was born into a Darwin-based family of Indigenous Australian descent from the Northern Territory (Wulwulam) and Queensland (Kukatj).
[1] His father, Russell, was a professional Australian rules footballer who played at the highest level for St Kilda before relocating to the Gold Coast to continue his AFL career with the Brisbane Bears.
[3] In June 2019, at 17 years of age, Jeffrey made his senior NEAFL debut for the NT Thunder at TIO Stadium and kicked a goal in his first game.
[7] Jeffrey spent the first half of the 2021 season playing for Gold Coast in the VFL and notably kicked a winning goal after the siren to defeat the Sydney Swans after marking the ball one handed with seconds to go in the game.
[8] He impressed again a month later with a 9-goal, best on ground performance in the VFL,[9] which earned him an AFL debut the following week against the Melbourne Demons at Metricon Stadium.