In the Grizzlies' season opener on October 17, 2018, Conley made his first regular season appearance since November 2017 after missing 70 games in 2017–18. He played nearly 29 minutes, scored 11 points and had three assists and one steal in a 111–83 loss to the Indiana Pacers. On November 2, he scored a season-high 28 points in a 110–100 win over the Utah Jazz. On November 10, he set a new season-high with 32 points in a 112–106 overtime win over the Philadelphia 76ers. On November 30, Conley improved his season-high scoring to 37 points and also made 10 assists in a 131–125 double-overtime win over the Brooklyn Nets. On March 5, 2019, Conley scored a career-high 40 points in a Grizzlies' 120–111 win over the Portland Trail Blazers. He was scoreless in the first quarter, Conley scored 19 of his career-high 40 points in the fourth quarter. On March 11, he was named Western Conference Player of the Week for games played from March 4 to March 10. It marked his first career Player of the Week award. On March 27, in a 118–103 loss to the Golden State Warriors, Conley passed Marc Gasol to become the Grizzlies' all-time leader in career points.