In April, Fox played in the 2016 Jordan Brand Classic, leading the East team to a 131–117 win while earning Co-MVP honors alongside Kentucky teammate Malik Monk.

[14] On March 17, Fox scored 19 points and 3 assists to defeat Northern Kentucky University in the first round of the NCAA tournament.

On March 24, In a Sweet 16 matchup against the UCLA Bruins, Fox scored 39 points to advance the Kentucky Wildcats to the Elite Eight game.

[15] In the Elite Eight, Fox only scored 13 points in a 75–73 loss to the North Carolina Tar Heels that ended the Wildcats season.

At the conclusion of his freshman season, Fox announced that he would forgo his final three years of collegiate eligibility and enter the 2017 NBA draft.

[16] As he stated in his announcement, "I think I’ve had a pretty good freshman season through the guidance of our coaching staff and I think it’s time for me to live out my dream.

Fox made his NBA debut for the Kings in their season opener on October 18, 2017, against the Houston Rockets, where he scored 14 points, 4 rebounds, and 5 assist in 24-plus minutes in a 105–100 loss.

On January 25, 2018, Fox scored 14 points, 4 assist and a putback slam dunk with 3.3 seconds left giving the Sacramento Kings the lead in an 89–88 win over the Miami Heat.

On January 28, 2018, Fox scored a season-high 26 points, going 6–6 from three-point range in a 15-point loss to the San Antonio Spurs.

On November 1, 2018, during a 146–115 win over the Atlanta Hawks, Fox notched his first career triple-double with 31 points, 10 rebounds, and 15 assists to bring the Kings to a 6–3 record, becoming the only player after LeBron James in 2005 to score a 30-point triple double before the age of 21.

[27] He was named the Western Conference Player of the Week for November 14–20 after leading Sacramento to a 3–0 record, where he averaged 25 points, 3.7 rebounds and 8 assists per game.

Fox and Anthony Edwards were announced as injury replacements for injured stars Stephen Curry and Zion Williamson.

[30] On February 24, Fox recorded a season-high 42 points, 12 assists, five rebounds and five steals in a 176–175 double overtime win over the Los Angeles Clippers.

[32] In Game 1 of the Kings’ first round playoff series against the Golden State Warriors, Fox put up 38 points in a 126–123 win.

[33] On April 19, 2023, Fox was named as the inaugural recipient of the NBA Clutch Player of the Year Award, winning over Jimmy Butler and DeMar DeRozan.

Fox is just the third player in NBA history to score at least 109 over two days, joining Kobe Bryant (2007) and Wilt Chamberlain (17 different times).

[41] On February 5, Fox made his debut for the Spurs, recording 24 points, five rebounds, 13 assists (matching his season-high) and three steals in a 126–125 win over the Atlanta Hawks.

[42] Listed at 6 feet 3 inches (1.91 m) and 185 pounds (84 kg),[43] Fox has primarily played the point guard position throughout his career.

[52] In February 2022, Fox was the subject of criticism after he shut down his personal NFT project “SwipaTheFox”, with more than $1.5 million in unpaid investment to approximately 100,000 investors.

Fox explained his decision in a Twitter thread, wherein he claimed he wasn't satisfied with the quality of the project so far and was shutting it down until the end of the NBA season, but did not answer critics who demanded a return of their investment.