Adnam was born and raised in Melbourne, Victoria and played junior basketball for the Mt. Evelyn Meteors. In 2013, Adnam played in the Victorian Youth Championship for the Kilsyth Cobras, a season which culminated in him scoring 37 points in the VYC Grand Final, to lead the Cobras to victory. He subsequently earned VYC All-Star Five honours and was named the league MVP. In 24 games for the Cobras in 2013, he averaged 17.7 points, 5.0 rebounds, 4.1 assists and 1.4 steals per game.
Professional career
In August 2013, Adnam was selected to train with the Adelaide 36ers during the NBL pre-season. The following month, he was named a 36ers' development player for the 2013–14 NBL season. He appeared in three games for the 36ers in 2013–14, scoring a total of four points. Following the conclusion of the NBL season, Adnam joined the Kilsyth Cobras for the 2014 SEABL season. In 28 games for the Cobras in 2014, he averaged 15.6 points, 3.3 rebounds and 3.7 assists per game. He subsequently earned SEABL Youth Player of the Year honours. Adnam's impressive first season in the SEABL earned him a development player spot on the Wollongong Hawks squad for the 2014–15 NBL season. He appeared in six games for the Hawks in 2014–15, scoring a total of eight points. Following the conclusion of the NBL season, Adnam re-joined the Kilsyth Cobras for the 2015 SEABL season. In 22 games for the Cobras in 2015, he averaged 17.5 points, 3.1 rebounds and 3.8 assists per game. He subsequently earned SEABL Youth Player of the Year for the second consecutive year, and was named to the All-SEABL Team. On 18 September 2015, Adnam signed with Melbourne United as a development player for the 2015–16 NBL season. On 12 February 2016, in the team's second last game of the season, with three starters resting in preparation for the finals, Adnam scored a team-high 16 points in 28 minutes off the bench in a 100–63 loss to the New Zealand Breakers in Auckland. United earned the minor premiership after finishing the regular season in first place on the ladder with an 18–10 win/loss record. However, in their semi-final series against the fourth-seeded New Zealand Breakers, United were swept 2–0 to bow out of the playoffs. Adnam appeared in eight games for United in 2015–16, averaging 2.3 points per game. Following the 2015–16 NBL season, Adnam re-joined the Kilsyth Cobras for the 2016 SEABL season. In 18 games for the Cobras in 2016, he averaged a career-high 18.6 points, 2.7 rebounds and 3.6 assists per game. Adnam re-joined Melbourne United as a development player for the 2016–17 NBL season. On 4 November 2016, Adnam scored a team-high 19 points off the bench in a 98–92 overtime loss to the New Zealand Breakers. United missed the playoffs in 2016–17 with a sixth-place finish and a 13–15 record. Adnam appeared in 20 games for United as a second-year player, averaging 3.6 points and 1.2 assists in 9 minutes per game. On 28 March 2017, Adnam signed with the Nelson Giants for the rest of the 2017 New Zealand NBL season. He made his debut for the Giants two days later, scoring 13 points in 40 minutes as a starter in a 100–94 overtime loss to the Southland Sharks. On 16 April 2017, he scored a game-high 26 points in a 79–74 victory over the Taranaki Mountainairs, helping the Giants claim their first win of the season after starting 0–6. He later picked up toe and quad muscle injuries mid-season which forced him to miss two games in early May. On 15 May 2017, he left New Zealand and headed to China to link up with Melbourne United for a two-game series against the Jiangsu Dragons. He re-joined Nelson by the end of the month, but continued to struggle with the toe injury for the rest of the season. In 11 games for Nelson, he averaged 16.6 points, 2.5 rebounds and 4.6 assists per game. On 7 April 2017, Adnam re-signed with Melbourne United on a two-year contract, earning elevation from a development player to the 11-man roster. In Melbourne's second game of the 2017–18 season on 14 October 2017, Adnam scored a career-high 23 points with six three-pointers in a 99–79 win over the Adelaide 36ers. In March 2018, he was a member of United's championship-winning team. In 30 games during the 2017–18 season, Adnam averaged 3.5 points per game. On 15 May 2018, he parted ways with United, in order to pursue opportunities elsewhere. On 4 December 2017, Adnam re-signed with the Nelson Giants for the 2018 season. On 5 May 2018, Adnam recorded 32 points and 14 assists in a 103–100 win over the Southland Sharks. He was subsequently named Player of the Week for Round 2. The Giants finished the regular season in second place with a 14–4 record, before losing to the Sharks in the semi-finals. In 18 games, he averaged 19.2 points, 2.8 rebounds, 5.7 assists and 2.1 steals per game. On 16 May 2018, Adnam signed with the Sydney Kings for the 2018–19 NBL season. In June 2018, he attended an NBA mini-camp run by the Dallas Mavericks. The Kings finished the regular season in third place with an 18–10 record before losing 2–0 to Melbourne United in the semi-finals, despite Adnam's equal team-high 13 points off the bench in game two. He appeared in all 30 games for the Kings in 2018–19, averaging 6.7 points, 1.1 rebounds and 1.3 assists per game. On 24 April 2019, Adnam signed a two-year deal with the South East Melbourne Phoenix.
National team career
In June 2017, Adnam was selected in the Australian Emerging Boomers squad for the Summer Universiade in Taipei.
Personal
Adnam's younger brother, Jorden, has also played for the Kilsyth Cobras.
