2015–16 season After going undrafted in the
2015 NBA draft, Cummings joined the
Houston Rockets for the
2015 NBA Summer League. On September 3, 2015, he signed with the Rockets, only to be waived by the team on October 23 after appearing in six preseason games. On November 2, he was acquired by the
Rio Grande Valley Vipers of the
NBA Development League as an affiliate player of the Rockets. On November 13, he made his professional debut in a 110–106 win over the
Idaho Stampede, recording 11 points and 5 assists in 32 minutes. On January 29, 2016, he was named in the West All-Star team for the 2016
NBA D-League All-Star Game. At the season's end, he was named to the
All-NBA D-League Second Team and All-Rookie Team. On April 29, 2016, Cummings left Rio Grande Valley and signed with
Dolomiti Energia Trento of the Italian
LBA for the rest of the season. On May 4, he made his debut with Dolomiti Energia in a 73–70 loss to
Juvecaserta Basket, recording 12 points, three rebounds and two steals in 18 minutes of the bench.
2016–17 season In July 2016, Cummings joined the
San Antonio Spurs for the
2016 NBA Summer League, and on July 24, 2016, Cummings signed with
Greek Basket League club
Aris Thessaloniki. In the semifinals of the
2017 Greek Cup, Cummings scored the game-winning lay-up against
AEK Athens, to give Aris the ticket to the Cup Final against
Panathinaikos Athens.
2017–18 season On July 17, 2017, Cummings signed a 1+1 year deal with the Turkish club
Darüşşafaka. Cummings helped Darüşşafaka to win the
2018 EuroCup title.
2018–19 season On July 6, 2018, Cummings signed with the German team
EWE Baskets Oldenburg for the 2018–19 season. He got honored with the MVP title and lead his team to the 2nd place in the regular season.
2019–20 season On July 7, 2019, Cummings signed a two-year contract with
Lokomotiv Kuban of the Russian
VTB United League.
2020–21 season Cummings averaged 12.8 points, 2.0 rebounds, 3.5 assists and 1.2 steals per game for Lokomotiv Kuban during the 2020–21 season.
2021–22 season On July 23, 2021, Cummings signed with
Metropolitans 92 of the
LNB Pro A.
2023–24 season On August 11, 2023, Cummings signed with the
South East Melbourne Phoenix in Australia for the
2023–24 NBL season. On December 8, 2023, he was released by the Phoenix, reportedly due to failing to meet off-court requirements on multiple occasions. In 12 games, he averaged 14.5 points, 3.3 rebounds, and 2.7 assists per game.
2025–26 season He signed a new 1-year contract with
Galatasaray on July 2, 2025. On March 15, 2026, Cummings was diagnosed with
sarcoidosis. ==Career statistics==