Exum was born in the Melbourne suburb of East Melbourne to American parents. He played for the Keilor Basketball Association as a junior and attended Lake Ginninderra Secondary College in Canberra in conjunction with the Australian Institute of Sport. He grew up also playing Australian rules football. In April 2013, Exum participated in the Nike Hoop Summit for the World Select Team, where he recorded 16 points, three rebounds and two assists in a 112–98 win over the USA Junior Select Team. In October 2013, he graduated from Lake Ginninderra and had the option to enroll in college and play college basketball during the 2013–14 season, but he decided against it. Exum competed for Lake Ginninderra in the Australian NationalHigh School Basketball Championships in December 2013, and helped them win the eventual title. On 28 January 2014, it was announced that Exum signed with agents from Landmark Sports and that he would declare for the 2014 NBA draft.
Professional career
Utah Jazz (2014–2019)
Exum was selected by the Utah Jazz with the fifth overall pick in the 2014 NBA draft. He made his NBA debut in the Jazz's season opener on 29 October, scoring five points in 9½ minutes off the bench in a 104–93 loss to the Houston Rockets. On 22 January, he scored a career-high 15 points on five 3-pointers in a 101–99 win over the Milwaukee Bucks. On 1 April, he had a career-high 12 assists in a 98–84 win over the Denver Nuggets. He appeared in all 82 games as a rookie and averaged 4.8 points, 1.6 rebounds and 2.4 assists in 22.2 minutes. Exum became only the 10th rookie in Jazz history to play in all 82 games, scoring in double figures in 13 games and leading the team in assists 11 times. He helped the Jazz to a 24–17 record as a starter and was selected to compete in the 2015 Rising Stars Challenge during the NBA's All-Star Weekend in New York. In August 2015, Exum sustained a tear of the anterior cruciate ligament in his left knee while playing for Australia in Slovenia. He underwent surgery and subsequently missed the entire 2015–16 season. Exum returned to action in the 2016–17 season. He played in 28 of the first 29 games of the season, but then sat out 10 of 11 games between 21 December and 10 January. On 11 March, he scored a career-high 22 points in a 112–104 loss to the Oklahoma City Thunder. In October 2017, Exum underwent shoulder surgery. He made his first appearance of the season on 15 March 2018, finishing with 10 points in a 116–88 win over the Phoenix Suns. On 30 March 2018, he scored a season-high 21 points in a 107–97 win over the Memphis Grizzlies. On 6 July 2018, Exum re-signed with the Jazz. On 27 December 2018, he scored a season-high 20 points in a 114–97 loss to the Philadelphia 76ers. Two days later, in his first start of the season, Exum had 13 points and a career-high 13 assists in a 129–97 victory over the New York Knicks. On 7 January 2019, he was ruled out for "a couple of weeks" due to an ankle sprain that he suffered two days earlier against the Detroit Pistons. His return was delayed after developing a bone bruise from his ankle sprain. He returned to action on 11 March against the Thunder after missing 25 games. Four days later however, he was ruled out indefinitely after sustaining a partially torn patellar tendon in his right knee.
Cleveland Cavaliers (2019–present)
On 24 December 2019, Exum was traded, alongside two second-round picks, to the Cleveland Cavaliers in exchange for Jordan Clarkson.
