In Moultrie's junior season at Raleigh-Egypt High School, he averaged 15 points, 8 rebounds and 2 blocks per game.

Moultrie averaged 13.2 points and 8.7 rebounds per game in the College Basketball Invitational as UTEP lost in the final round to Oregon State.

In the Conference-USA Tournament, Moultrie averaged 12.0 points per game and earned a spot on the all-tournament team.

[15] In March 2018, Moultrie signed with the NLEX Road Warriors of the Philippine Basketball Association as their import for the 2018 PBA Commissioner's Cup.

[17] His first game for the team was in the VTB United League as he scored 16 points and grabbed 9 rebounds in 26 minutes against Parma as Kalev/Cramo won 93–82.

[18] In December 2019, Arnett moved to the Beijing Royal Fighters of the Chinese Basketball Association.

[20] On March 28, 2021, Moultrie scored 37 points and grabbed a career-high 34 rebounds in a 105–95 victory over the Jiangsu Dragons.

[27] On February 7, 2025, Moultrie signed with the Kaohsiung Aquas of the Taiwan Professional Basketball League (TPBL).

March 2022)[29] Moultrie represented the U-19 United States national team at the 2009 U-19 World Championship held in New Zealand, where they won the gold medal.