In his fifth NBA season, Booker appeared in 62 games for the Suns and averaged a career-high 35.9 minutes. He posted 26.6 points, 6.5 assists, 4.2 rebounds and 0.7 steals, while shooting career-bests from the field (48.9% FG) and the free-throw line (91.6 % FT). Booker also hit 35.4 percent of his 5.7 three-point attempts per game. On opening night against the Kings, Booker went for 22 points and 10 assists -- his second-highest passing total of the season, and a number he'd match seven more times. Against the Trail Blazers on Mar. 6, he recorded a season-high 12 assists, adding 23 points, five rebounds and a steal. Booker scored at least 20 points 48 times, topping out with 44 points, nine assists, eight rebounds, and two steals in a win over New Orleans on Dec. 5. In that game, Booker went 13-of-13 at the line. Against Minnesota on Nov. 23, Booker went for 35 points, 12 rebounds and nine assists. In a win in Boston on Jan. 18, he posted 39 points, 10 rebounds, nine assists and two steals. Booker hit a season-high six three-pointers (6-10 3PT) in a win over Golden State on Oct. 30. He went for 40 points, six assists and two boards against Memphis on Jan. 5. After the All-Star break, Booker averaged 24.5 points, 7.9 assists and 4.0 rebounds in 10 games before the season was suspended on Mar. 11. When play resumed in Orlando, Booker went on a tear, leading the Suns to a perfect 8-0 record during seeding play. While Phoenix ultimately fell short of a playoff berth, Booker averaged 30.5 points, 6.0 assists, and 4.9 rebounds per game, while shooting 50.3 percent from the field in the bubble. For his efforts, Booker was named to the NBA's All-Bubble First Team.

Booker started 64 games for the Phoenix Suns during the 2018-2019 season, his fourth year in the league. He set new career highs in terms of points per game (26.6 ppg) and assists per game (6.8 apg). The scoring uptick allowed him to finish with the sixth-highest per-game average in the league, while also posting a career-best 46.7 percent shooting from the field. Furthermore, Booker played a career-high 35.0 minutes per game, which was the seventh-most in the NBA. On Jan. 24, Booker scored 27 points against the Portland Trail Blazers and in the process became the fifth-youngest player in NBA history to score 5,000 career points. He scored a season-high 59 points against the Utah Jazz on March 25. In the following game, he put up another 50 points against the Washington Wizards, making him the youngest player in NBA history with back-to-back 50-point games. In a triple-overtime game against the Wizards on Dec. 22, Booker set a new career high for assists in a game with 14. He finished with 1,700 points, which was the 15th-highest total in the league. Booker also finished ninth in the league with 393 made free throws, due largely to a career-high in attempts (454).

Booker continued to evolve into one of the league's most talented young scorers in 2017-18. Although he was limited to 54 games due to injury, Booker was as explosive as ever when healthy. He led Phoenix with a career-best 24.9 points per game, ranking 10th in the NBA. The ex-Kentucky Wildcat also established his best per-game marks in rebounds (4.5), assists (4.7) and three-pointers (2.7). Meanwhile, he shot the ball at the highest clip of his career across all three major categories: field goals (43.2%), three-pointers (38.3%) and free throws (87.8%). Booker's advanced stats told a similar story; he posted a 56.1 TS% and 50.1 EFG%, both career-highs. The former lottery pick exploded for 46 points in a win over Philadelphia on Dec. 4, making 17-of-32 field goals including 5-of-8 from deep. The performance was one of three during the 2017-18 campaign in which Booker scored 40 or more points. He also collected four double-doubles on the season, including a 40-point, 10-rebound showing against Memphis on Feb. 26. That performance came in the midst of a hot streak in which Booker surpassed the 30 point mark in four straight contests. Over that stretch, he averaged 35.7 points and 7.8 rebounds per game while shooting 46.9% from the field.

Booker turned the corner from high-upside rookie to arguably the team's best all-around player in 2016-17. It took him just five games to set a new career high with 38 points Nov. 2 against Portland, and he set a new mark with 39 the very next game against the Lakers. On March 24 against Brooklyn, the then 20-year-old racked up 70 points across 45 minutes in a 130-120 loss to Boston. Booker went 21-for-40 from the field in that contest, also collecting eight rebounds, six assists and three steals. He was such a key piece of the Phoenix offensive scheme that he ended up finishing 14th in the entire league in both minutes played (2,730) and field goals attempted (1,431) across 78 games. Booker led the team in scoring at 22.1 ppg, joining Eric Bledsoe (21.1 ppg) as the only 20-point scorers. He also tallied a team-high 147 three-pointers made, converting them at a success rate of 36.3 percent. Booker and the Suns finished the season with a record of 24-58 and missed the postseason.

Booker was drafted by the Phoenix Suns in the 1st round (13th pick) of the 2015 NBA Draft. Little did the league know at the time that Booker would ultimately represent one of that draft's best value picks. The Kentucky product made his NBA debut on Oct. 28 against Dallas, making an immediate impact off the bench with 14 points and three rebounds. He missed time over the next two weeks, due partially to a minor ankle injury, but by late December, Booker had locked down a starting spot and never looked back. It was the turn of the calendar year to 2016 when Booker took a massive leap forward, however. Through the season's last 47 games, he averaged 18.3 points on 41.1 percent shooting, seeing 35.0 minutes per contest and starting all but one of those contests. Booker had four 30-point games in the month of March, posting a career high of 35 points on March 10 against the Nuggets. When it was all said and done, Booker appeared in 76 games (51 starts) during his rookie season, and he finished the year with averages of 13.8 points, 2.6 assists and 2.5 rebounds. He finished third on the team in scoring and fourth in minutes played. Booker was awarded First-Team All-Rookie honors at the end of the year and received several second-place nods in the Rookie of the Year voting.