He was born in Sydney to Fijian parents, and his family moved to Perth, Western Australia after his father's death.

[3] After his father's death, his mother moved the family to Perth, Western Australia, where her brother lived.

[6] Naitanui also played basketball as a junior for the Perry Lakes Hawks[7][8] and excelled at track and field events, particularly high jump.

[9] In the 2007 Under-18 AFL National Championships, Naitanui was dominant in the ruck for Western Australia, and was named Best on Ground in the final.

[10] He was named in the Under-18 All-Australian Team in both 2007 and 2008, and was awarded a scholarship with the Australian Institute of Sport to become a member of the AIS/AFL Academy Squad.

[6] The Melbourne Football Club, who retained that pick, had looked at Naitanui, but instead selected Victorian Jack Watts.

His career suffered a setback, however, during pre-season training when he experienced knee soreness and had precautionary surgery.

[13] Naitanui impressed enough in the WAFL in a game where he accumulated 15 possessions, 21 hit-outs, 4 goals and a spectacular mark, to earn his selection in the round 12 against Richmond at Etihad Stadium.

[14] In his second game against premiers Hawthorn at Subiaco, Naitanui was quiet for the first three-quarters but dazzled in the fourth, kicking three goals and leading his team to a come-from-behind win.

In March 2012, a viral video of Naitanui performing a slam dunk at a Perth Wildcats basketball game received over 100,000 views on YouTube.

On the Friday Night game against North Melbourne in round 8, 2013, Naitanui took a memorable pack mark 30m out with seconds left on the clock.

[17] In round 21, during the 2016 season, Naitanui kicked a goal with 4 seconds remaining against the GWS Giants, winning the game for the Eagles.

[26][27] Naitanui features in the 2021 fly-on-the-wall documentary TV series Making Their Mark, which showed the impact of the COVID-19 pandemic on several AFL clubs, players, and staff.

[28][29] He and Eddie Betts were filmed almost continuously, with other players featured including Stephen Coniglio and Rory Sloane, along with several coaches and other staff associated with the clubs.