In his second NBA season, Okobo appeared in a career-high 55 games, despite the regular season being suspended on Mar. 11. In 13.1 minutes per game, Okobo posted averages of 4.0 points, 2.1 assists, and 1.6 rebounds. He hit 39.8 percent of his field goals, 35.2 percent of his threes, and 70.4 percent of his free throws. Okobo scored in double-figures for the first time on Nov. 21 against New Orleans, finishing with 11 points and seven assists in 20 minutes. He went for 16 points and four assists on Nov. 24 in Denver. Three nights later, Okobo established a season-high with eight assists, to go with 13 points, in 21 minutes against Washington. He made his first of three starts on Dec. 21 against Houston, posting a season-high 17 points, four rebounds, three assists and one steal. Against Golden State on Feb. 29, Okobo went for 14 points, seven rebounds, and five assists. On Dec. 20 in Oklahoma City, Okobo posted 11 points with season-highs in steals (three) and blocks (two). Okobo appeared in one game for the Suns during the Orlando restart, playing 12 minutes off the bench in an Aug. 13 win over the Mavericks.

Okobo's role built gradually during his rookie campaign, as his NBA debut saw him score two points and collect an assist during a 121-100 win over the Dallas Mavericks. Later in the month, Okobo finished a 117-110 loss to the Thunder with 18 points, five rebounds and seven assists. When it was all said and done he started 16 of 53 games as a Sun in 2018-19 and finished the year averaging 5.7 points and 2.4 assists in 18.1 minutes per contest. He did have a few more standout performances, however. His highest-scoring game was Nov. 28 against the Clippers, when he totaled 19 points on 8-of-12 shooting. On Feb. 2, Okobo dished out a season-high 11 assists in a six-point loss to the Atlanta Hawks. The 6-3 point guard ultimately reached double figures in nine games, including three out of his last four contests. Okobo averaged 10.2 points in five contests in the month of April, as he started to see an expanded role with the Suns out of the postseason and several key rotation pieces dealing with nagging injuries. One of which was fellow point guard Tyler Johnson, who was acquired in a February deal but had his season cut short due to a knee injury. This allowed Okobo to step in as the backup to De'Anthony Melton during the final stages of the year.