In his second NBA season, Milton appeared in 40 games for the 76ers, making 24 starts and averaging 20.1 minutes per game. The 2018 second-round pick posted career-highs in points (9.4 PPG), rebounds (2.2 RPG) and assists (2.6 APG) per game, while also notching career-bests in field goal (48.4%), three-point (43.0%) and free throw (78.5%) percentage. Milton became a regular in the rotation in January and made his first start of the season on Jan. 25 against the Lakers. In that game, Milton finished with seven points, nine rebounds, and three assists. In a Jan. 30 matchup against Atlanta, Milton posted 27 points, including five three-pointers, to go with five rebounds and six assists. He went for a career-high 39 points against the Clippers on Mar. 1, going 7-of-9 from beyond the arc. Over his final seven games before the suspension of the season, Milton averaged 19.4 points, 4.1 assists, 2.4 rebounds, 1.3 steals and 0.6 blocks, while shooting 60.5 percent from three. Milton started all four of the Sixers' postseason games in Round 1 against Boston. He made his playoff debut in Game 1 of the series, going for 13 points and three assists. Milton established a playoff-career-best with 17 points in Game 3.

Milton came off the bench to play 20 games with the 76ers during the 2018-19 season. He averaged 4.4 points and 1.8 rebounds per contest in limited playing time. Milton came off the bench to make his season debut against the Washington Wizards on Nov. 30. In that game, he scored five points and contributed a pair of assists. Milton scored a career-high 13 points against the Orlando Magic on Mar. 25. His career high in rebounds came Apr. 9 against the Miami Heat when he pulled down eight boards. As a two-way player, Milton also competed regularly for the Delaware Blue Coats of the G League. For the Blue Coats, he started 27 games, averaging 24.9 points and 5.3 assists. That scoring rate was good for fourth in the league.