As a freshman, Payne averaged 16.8 points, 5.4 assists, 3.6 rebounds and 1.7 steals per game. He was forced to start at point guard as a freshman due to an injury to Zay Jackson, and began his collegiate career registering 21 points, five boards and four assists in the team's opener at Valparaiso. Payne earned first-team All-OVC honors and was named freshman of the year by the conference. As a sophomore, he was the Ohio Valley Conference Player of the Year after he averaged 20.2 points, 6.0 assists, 3.7 rebounds and 1.9 steals per game. Payne opted to declare for the NBA Draft after his sophomore season.
On June 30, 2020, Payne agreed to a two-season deal with the Phoenix Suns. He made his debut on July 31 in the 2020 NBA Bubble, where he recorded 9 points, 3 rebounds, 2 assists, and 2 steals on a plus-minus of +21 in a 125–112 win over the Washington Wizards. On August 7, 2020, Payne recorded a season-high 15 points in a 114–99 win over the Indiana Pacers. He later repeated his season-high in a blowout 128–102 win over the Dallas Mavericks, helping the team be undefeated in all eight games the Suns played in the bubble while coming off the bench and having his highest scoring and rebounding season averages in the NBA yet.
After his successful time in the bubble, Payne had his second season option picked up on November 18, 2020. In his second season with Phoenix, Payne continued the successful production he had in the 2020 bubble off the bench. On January 6, 2021, he tied his career-high of 10 assists in only 16 minutes of play in a 123–115 win over the Toronto Raptors. On February 20, he scored a season-high 19 points and put up 7 assists in a blowout 128–97 win over the Memphis Grizzlies. On March 4, Payne recorded his second career double-double in the NBA, leading the Suns that night with 17 points and 10 assists coming off the bench in a 120–98 blowout win over the Golden State Warriors.
Payne attended Lausanne Collegiate School in Memphis, Tennessee. He grew from 5'5' as a freshman to 6'0 as a senior. Despite leading Lausanne Collegiate to a 2013 Division II state title in Tennessee, Payne was not a heavily scouted player by collegiate programs. He was considered to be a three-star recruit by Rivals.com and was not ranked in the top 100 prospects. He was recruited by William Small to play college basketball at Murray State, choosing the Racers over a few other schools. Payne then went from a little-known college recruit to a potential NBA lottery pick.