Cooks was born in Ballarat, Victoria to father Eric and mother Josie. His father is an African-American expatriate who became a naturalised citizen of Australia, and his mother is Australian. He was raised alongside siblings Georgia and Dominique, the latter of which formerly played professional basketball for the Illawarra Hawks. His father played college basketball for St. Mary's College in California before relocating to Australia to pursue a professional career in the South East Australian Basketball League and National Basketball League. The family moved to Wollongong when Xavier was a young age as his father accepted an assistant coaching role with the Illawarra Hawks.
College career
He chose to attend Winthrop over offers from schools such as UC Santa Barbara, Boise State, Hartford, Maine, and Nicholls State. On 15 February 2017, Cooks recorded the first 20-point, 20-rebound game for Winthrop since 2003. At the close of the season, he was named first-team All-Big South Conference. In 2017, Cooks was named to the Australian "Emerging Boomers" squad for the 2017 Summer Universiade. In the 2017–18 season, senior Cooks became Winthrop′s all-time leading rebounder. At the close of the Big South regular season, Cooks was again named first-team All-Big South and the Big South Player of the Year. In 2020, two years after graduating from Winthrop, he was voted into the Big South Men's Basketball All-Decade Team.
Professional career
After going undrafted in the 2018 NBA draft, Cooks joined the Golden State Warriors for the 2018 NBA Summer League. On 27 July 2018 Cooks signed with S.Oliver Würzburg. Cooks joined the Phoenix Suns for the 2019 NBA Summer League. In July 2019, Cooks signed with SIG Strasbourg of the French LNB Pro A league. On 7 August Cooks was injured at training and was later released from SIG Strasbourg. On 27 November 2019 Cooks signed with the Sydney Kings of the Australian NBL on a multi-year deal. He opted out of his contract with the Kings on 2 May 2020 due to the salary cuts that were implemented by the NBL to protect the league during the coronavirus pandemic. After exploring his options, on 7 July 2020 Cooks re-signed with the Kings on a one year deal.
National team career
In early August 2019, Cooks made the final cut for Australia's 2019 FIBA World Cup roster. However, one week later he was forced to withdraw from the competition due to a knee injury sustained during practice.
