Born in the Sydney suburb of Caringbah, Humphries grew up in Cronulla and started playing basketball at the age of 12. He had earlier played rugby league. In 2010, he spent six months in Hamilton, Ontario, Canada. "I had a pretty big growth spurt when I lived in Canada", he told theleader.com.au in January 2014.
College career
Humphries attended Scots College in Sydney and the Australian Institute of Sport in Canberra before taking his game to the United States in December 2014 to play prep ball at La Lumiere School in La Porte, Indiana. Humphries enrolled at the University of Kentucky in 2015 and saw action in 23 games as a freshman. Coming off the bench in all but one game, he averaged 1.9 points and 2.4 rebounds in 9.1 minutes per contest. In the 2016–17 campaign, Humphries appeared in 38 games for the Wildcats with one start, producing averages of 2.8 points and 2.8 boards per outing in 8.3 minutes a game. He scored a career-high 12 points in his last college game, Kentucky’s 73-75 loss to the North Carolina Tar Heels in the South Region finals where he was also named in the NCAA All-Regional tournament team. In April 2017, Humphries declared for the NBA draft, forgoing his final two years of college eligibility.
Opting to turn professional, Humphries worked out with several NBA franchises over the summer, including the Washington Wizards, after going undrafted in the 2017 NBA draft. Humphries returned to Australia and signed with his hometown team the Sydney Kings on 27 July 2017 for the 2017–18 NBL season. With the Kings, Humphries averaged 6.9 points, 3.6 rebounds and 1.0 blocks while shooting 58 percent in 16 minutes per game, making six starts in 26 appearances. He was subsequently named the NBL Rookie of the Year.
On 8 October 2018, Humphries signed a training camp deal with the Atlanta Hawks, but was later waived the day after. Humphries was added to the training camp roster of the Erie BayHawks in October 2018.
Atlanta Hawks (2019)
On 1 April 2019, the Atlanta Hawks announced they had signed Humphries for the remainder of 2018–19 season, after the end of the 2018/2019 season Humphries was waived by the Hawks. Humphries joined the Los Angeles Clippers for the 2019 NBA Summer League in Las Vegas.
On 24 September 2019, Humphries signed with the Orlando Magic. He was waived and assigned to the Lakeland Magic. Humphries averaged 8.8 points, 5.9 rebounds, and 1.6 blocks per game during the 2019-20 season.
Adelaide 36ers (2020–present)
On 16 July 2020, Humphries signed a two-year deal to return to the NBL with the Adelaide 36ers.
