Melton played in 36 games, starting in the last 25 games of the season that year. He averaged 8.3 points, 3.5 assists, 4.7 rebounds, and 1.9 steals per game. On January 25, in an 84–76 win over future #2 pick Lonzo Ball and UCLA, Melton had 13 points, 9 rebounds, 5 assists, 4 steals, and a block. He followed this performance with a 16-point, 7 rebound, 6 assist, 6 steal, and 2 block game against future #1 pick Markelle Fultz and Washington on February 1. Melton became the first freshman to record at least 300 points, 150 rebounds, 100 assists, 60 steals, and 35 blocks in their starting season since Dwyane Wade. As a result of those starts, he was projected to be a key player for USC's upcoming season.
Sophomore year
On September 26, 2017, federal prosecutors in New York announced charges of fraud and corruption against 10 people involved in college basketball, including USC assistant coach Tony Bland. The charges allege that Bland and other members involved allegedly received benefits from financial advisers and others to influence student-athletes to retain their services. Following the announcement, USC indefinitely suspended Melton in relation to the scandal due to a family member's involvement there. On February 21, 2018, Melton announced he would withdraw from USC and declare for the 2018 NBA draft.
Melton was selected with the 46th pick by the Houston Rockets in the 2018 NBA draft. He played for the Rockets during the 2018 NBA Summer League in Las Vegas. In five games, Melton recorded 16.4 points, 7.2 rebounds, 4.0 assists, and 3.0 steals per game. His best game during the event was on July 9 where he made 26 points, 10 rebounds, and 5 assists in a 104–90 win over the Los Angeles Clippers. On August 31, Melton was traded alongside Ryan Anderson to the Phoenix Suns in exchange for Brandon Knight and Marquese Chriss. Melton signed his first NBA contract with the Suns on September 21. He made his professional debut with the Suns on October 22, 2018, in a 123–103 loss to the Golden State Warriors, but did not record significant playing time until October 31 in a 120–90 loss to the San Antonio Spurs. Melton was assigned to the Northern Arizona Suns, Phoenix's development team in the NBA G League, for their first game of the season on November 3, 2018. He played the one game, a 118–108 loss to the Santa Cruz Warriors, and was recalled to Phoenix the next day. On December 4, Melton recorded a professional high of 21 points in a 122–105 loss to the Sacramento Kings. He also recorded season-high 10 assists in a 102–93 win over the Denver Nuggets on January 12, 2019. Melton shined on the defensive end of the court as well as put his playmaking skills on display in the Suns victory against the Sacramento Kings on January 8. Melton scored 10 points with eight assists, four rebounds, four steals and two blocks in the win. Melton later suffered a right ankle sprain on January 24, leaving him out of action for close to a month before returning briefly for the NBA G League on February 20, and then played in the NBA proper three days later against the Atlanta Hawks. On March 16, Melton recorded a career-high 8 rebounds in a 138–136 overtime win over the New Orleans Pelicans. Melton was 2nd in the NBA in rookie steals in 2018–19 with 1.36 spg. When Melton is on the floor, he recorded steals more frequently than any other player in the NBA, ranking 1st with 3.3 steals per 100 possessions. Among rookies to start in majority of their appearances, Melton's 3.3 steals per 100 possessions are tied for 6th most all-time in Basketball-Reference's database.
Memphis Grizzlies (2019–present)
On July 7, 2019, the Suns traded Melton, Josh Jackson, and two second round picks to the Memphis Grizzlies in exchange for Jevon Carter and Kyle Korver.
