Coates was born in Port Moresby, Papua New Guinea to a mother from the Gulf Province in PNG and an Australian father.

As an infant he moved with his family to Australia and initially spent two years living in Cairns before settling on the Gold Coast.

[3] His goal was to represent Papua New Guinea at the Olympics[4] but former NRL player and Marymount teacher Matt Geyer organised a phone call with then-Queensland captain Greg Inglis[5] and the pair convinced Coates to pursue a career in rugby league instead.

[6] Coates named Inglis as his sporting idol growing up[7] and was nicknamed 'Little GI' by his Broncos teammates due to the similarities in playing style.

[8] Xavier Coates began playing junior football on the Gold Coast for the Currumbin Eagles[9] in 2010 at the age of 9 years old.

After a brief pursuit of an athletics career, he returned to the field and played part in the Currumbin Eagles' undefeated premiership winning Under-16 team in 2017.

[15] In 2019 he was fast tracked[16] to senior rugby league with the Currumbin Eagles,[citation needed] making his Queensland Cup debut for the Tweed Heads Seagulls, however as he was not a contracted Gold Coast Titans player, he was transferred to Broncos' feeder club Redcliffe Dolphins.

[28] In round 1 of the 2022 NRL season, Coates made his club debut for Melbourne on his 21st birthday against Wests Tigers, scoring a try in a win at CommBank Stadium.

[30] Coates would finish the 2022 season with 16 tries from 17 appearances for Melbourne, with an ankle injury suffered in game one of the 2022 State of Origin series sidelining the winger for seven matches.