Richardson attended Trenton Catholic Academy his freshman year, then spent his sophomore year at Roselle Catholic High School before returning to Trenton Catholic Academy for his junior and senior years,[1] to team back up with coach Fred Falchi, who came out of retirement to coach. In his high school career at Trenton Catholic Academy, Malachi scored a total 1,245 points, averaging 19.2 points in his junior year and 18.7 in his senior year.[2] Richardson was rated as a four-star recruit and ranked 23rd overall recruit and fifth-best shooting guard in the 2015 high school class.[3]
Richardson played one season of college basketball for Syracuse, averaging 13.4 points, 4.3 rebounds and 2.1 assists per game.[4] Richardson was also named to the ACC All-Freshman team.[5] On April 18, 2016, he declared for the NBA draft, forgoing his final three years of college eligibility.[6][7]
On June 23, 2016, Richardson was selected by the Charlotte Hornets with the 22nd overall pick in the 2016 NBA draft.[8] His rights were later traded to the Sacramento Kings on July 7, 2016, in exchange for Marco Belinelli.[9] On July 15, 2016, he signed his rookie scale contract with the Kings.[10] On February 16, 2017, he was ruled out for four to six weeks after suffering a partial thickness tear of his right hamstring the night before.[11][12] He was later shut down for the remainder of the season on March 26, 2017.[13][14] During his season-and-a-half with the Kings, he had multiple assignments with the Reno Bighorns of the NBA G League.[15]
Toronto Raptors (2018–2019)
On February 8, 2018, Richardson was traded to the Toronto Raptors in exchange for Bruno Caboclo.[16] On February 11, in Charlotte, he played in his first game with the Raptors.[17] During the rest of the season, he received multiple assignments to Raptors 905, Toronto's G League affiliate.[18]
On February 6, 2019, Richardson was traded to the Philadelphia 76ers,[19] by whom he was waived the following day.[20]
On August 17, 2019, Richardson signed with Hapoel Holon of the Israeli Premier League for the 2019–20 season.[22] On November 30, 2019, Richardson recorded a career-high 24 points, while shooting 6-of-7 from three-point range, along with five assists in a 109–95 win over Ironi Nahariya.[23] In 15 games played for Holon, he averaged 11.6 points and 2 assists per game. On December 14, 2019, he parted ways with Holon.[24]
Vanoli Cremona (2019–2020)
On December 16, 2019, Richardson signed with Vanoli Cremona in the Italian Lega Basket Serie A as a replacement for Vojislav Stojanović.[25] However, he had an unfortunate experience in Cremona: one month after his debut with the team he fractured his right hand[26] during the match against Virtus Roma on January 26.[27] He underwent a surgery[28] and was released from the team on February 11.[29]
Canton Charge (2021)
For the 2020–21 season, Richardson joined the Canton Charge of the G League[30] where he played 15 games, averaging 8.4 ppg while shooting 46% from beyond the arc.[31]