Acy played seven seasons in the National Basketball Association (NBA) for the Toronto Raptors, Sacramento Kings, New York Knicks, Dallas Mavericks, Brooklyn Nets and Phoenix Suns.

[4] He ranked sixth on the team in scoring (5.4) and fourth in rebounding (3.6), while leading Bears in blocked shots (34).

In the first round of the Big 12 men's basketball tournament, Acy recorded a team-high 21 points and a career-high 15 rebounds in a loss to Oklahoma.

Following the season, he earned the Big 12 Sixth Man Award and was named All-Big 12 Honorable Mention.

[9] On December 9, 2013, Acy was traded, along Rudy Gay and Aaron Gray, to the Sacramento Kings in exchange for Greivis Vásquez, Patrick Patterson, John Salmons and Chuck Hayes.

[10] Six days later, he made his debut for the Kings in a 106–91 win over the Houston Rockets, recording four points, three rebounds and one block in 13 minutes off the bench.

[11] On August 6, 2014, Acy was traded, along with Travis Outlaw, to the New York Knicks in exchange for Wayne Ellington and Jeremy Tyler.

[12] He made his debut for the Knicks in their season opener on October 29, 2014, recording six points, six rebounds, one assist and one block in 21 minutes off the bench in a 104–80 loss to the Chicago Bulls.

[14] He had a career-best season in 2014–15, averaging career highs in points (5.9), rebounds (4.4), assists (1.0), minutes (18.9) and games played (68).

[19] On November 28, 2016, Acy was acquired by the Los Angeles D-Fenders of the NBA Development League and then immediately traded to the Texas Legends, the Mavericks' D-League affiliate.

[20] On December 1, 2016, he made his debut for the Legends in a 121–106 win over the Greensboro Swarm, recording 16 points, seven rebounds and two blocks in 17 minutes as a starter.

[32] On November 16, 2019, Acy recorded a new career-high 22 points, shooting 9-of-12 from the field, along with six rebounds and six dunks in a 94–57 win over Maccabi Ashdod.